Mostly it feels set or hand placed. I’ve had to reload and opened a few containers that had sellable junk, gold, and the type of sellable junk (jewelry, precious stones, amount of gold pile) has changed a bit. But if you loot a corpse with a Ring of Protection +2 on it and reload, it will have that same ring every time. I’d say 90% of the loot is hand placed, or more.