Since you guys have finished your first encounter in this quest, I should take a minute to explain how Treasure and XP work in B/X D&D. I was going to wait until the party made it to Hommlet, but we might as well take a look at it now. There are some pretty important things about the B/X system that should be understood:
1.
Treasure enemies carry is randomly determined based on the monster's Treasure Type (TT). Every monster has a Treasure Type. Using gnolls as an example, a gnoll has a TT of "D".

When I check the Treasure Table for enemies with a TT of "D", you see that this encounter gives the players the following odds for finding certain treasure types:

Sometimes, based on what I roll according to the TT, a slain enemy will be carrying no loot at all. Especially if the percentages are really low for each treasure artifact. Other times, a relatively weak enemy might be hoarding an almost gamebreakingly huge amount of loot. Regardless, I always go by what I randomly roll when I check the enemies' TT after an encounter. As DM, I never stray from following the TT based on the encounter.
2.
B/X D&D made treasure highly important to gaining Experience. In B/X D&D, not only is XP awarded for slaying enemies, but also for collecting loot. XP is awarded for loot at a rate of 1XP/Gold coin (or equavalent value). So if you kill a minster and it had 50 gold coins on it, you'll get 50XP for looting that gold. If the slain monster had 30sp on it, you will be awarded 3 XP for looting it (30 silver equals 3 gold, so you earn 3XP for the gold value of the silver).
That said, monsters slain give very little XP by themselves. For example if we compare a gnoll form 5e with a gnoll from B/X, a 5e gnoll is worth 100xp but you get nothing for looting it. In B/X, a gnoll is worth only 20xp if you defeat it, but you also earn XP if you loot it equal to the value in gold of any treasure claimed. Maybe that means you get nothing because there was no loot on it, maybe that means you get 3000 gold coins because that's what the DM rolled the encounter had.
It should also be noted that a slain enemy doesn't always have all of their loot on their person.
Especially if it's a high amount of treasure they are carrying. In the case of the gnolls, it's really unlikely that such savage beasts would be carrying 3000gp among them. Even 1000gp apiece is not realistic. So sometimes, as a DM, I may stash the loot somewhere in the vicinity. It may not be easy to find. If you kill a bunch of gnolls and they aren't carrying anything on them, it may be because I rolled poorly (for you) on the TT table, or it may mean I rolled well (for you), on the TT table, but there's no logical reason the monsters would be carrying all that loot, so it's hidden or stashed somewhere. Often if loot is stashed, I may leave clues as to where it might be and why it might be there. Sometimes I don't leave any clues and it's on the PCs to interact with their environment and maybe turn something up.
3.
PCs don't get any XP awarded until they actually make it back from a dungeon/wilderness safely. You can kill a hundred goblins, loot fifty dead bandits, and trick a dragon out of its entire horde, but until you get yourselves out of the dungeon and back to a town with inn or somewhere to rest, recover, and resupply, no XP is awarded. That means you never advance to the next level, mid-adventure. You
have to find somewhere to sit and ponder upon your journey so far to gain any experience from it, and you will always "level up" between quests, or delves, or what have you.
4.
XP gained from slaying monsters or collecting loot is divided among the surviving PCs equally. If five PCs enter a goblin stronghold, kill 100XP worth of enemies, and collect 1000XP worth of loot, no XP is actually awarded yet. If on the way back to the inn they are using as a base of operations, one PC is killed in a random encounter or some other reason, and only four PCs make it back, only the four surviving PCs will collect XP for their efforts. It will be divided equally among the four survivors
before XP bonuses are calculated. So each PC will earn 25XP for slaying monsters (100/4=25), and 250XP for the loot they hauled back (1000/4=250). Each PC will have earned 275XP, and then they may calculate any XP bonuses or penalties they get for based on their Prime Requisite scores.
XP earned through collecting loot is always divided equally among surviving PCs, but material treasure collected is determined by the party. So from that 1000 gold looted and divided between the four surviving PCs, each PC earns 250XP before bonuses are calculated. However, the four surviving PC's decide who gets what percentage of the loot in terms of actual gold you can spend. Maybe two PCs did nothing to aid the other two and the party determines that the two that did all the work can split the gold equally between them 50/50. That means that two PCs have 0 gold added to their treasure, two PCs have 500 gold added to their inventory, but all PCs earned 250XP from the loot that was brought back.
So how treasure is divided for the purposes of spending wealth is up to the party, but how it's divided for the purposes of earning XP is always split evenly among the surviving PCs.
5.
You can never advance more than one Level after XP is awarded. Say, for example, a Level 1 Thief, currently with 200XP, needs a total 1200XP to advance to Level 2, and 2400XP to advance to Level 3. They return from an adventure and after all the gold is tallied out, the Thief earns 3200gp. They do not get 3200XP. They cap out at whatever they need to reach the next level. So in this case the Thief earns 3200gp to spend as money, but they only earn 1000XP (the amount of XP needed to advance a level), and are now Level 2. The remaining XP is scratched/ignored. For this reason, it is impossible to enter a dungeon at Level 1 and return at Level 3 or higher, and it often benefits a PC to only collect as much loot as they think will get them to the next Level, and return for the rest later. You can haul back as much as you can carry if you like, but to get the most benefit from the loot in terms of XP earned, it may be better to haul it out in increments.
Also, this isn't really a rule, but something I should say. Because loot turns into XP, and there's the possibility of earning a ridiculous amount of loot on a relatively low level encounter, one question I have always been confronted with is why a 1st or 2nd Level adventurer might be interested in continuing to put their life at risk if they managed to haul in a amount of treasure that would basically make them rich. The one solution to this problem (aside from many DMs' advice to just "flub" the treasure rolls, which in keeping with true B/X rules adherence I find distasteful), is to remind the players that killed PCs can be brought back to life by a high enough level Cleric with a Raise Dead spell. Oftentimes a DM will require the party to go on some sort of side quest to revive a dead PC, and I will always leave that option open as well, but sometimes a Cleric doesn't need a side quest done for him/her, or the PCs are too busy to get sidetracked. In these cases the cleric performing the spell may just require a sizable monetary donation to their church or temple. I generally allow the PCs to "buy" their fellow party members a Raise Dead spell instead of going on a sidequest, but usually the costs of buying a Raise Dead spell are prohibitively high for a low-level party (usually somewhere between 10k-20k gold). So oftentimes a party or a PC may want to set aside some extra loot in case they want to bring a PC back to life without going on a dangerous sidequest.