While this is probably an easy task once you know where to go the big trick is getting there. While the monster hunter hacking scene (if it even is that game) is not nonexistent it is also not the biggest and tends to look at other things.
Assuming it is even a database of drop rates, or value associated with each monster/item like any other stat for them, and not some kind of assembly driven affair (looking up things in a database or stats table to plug them into a formula is annoying and tedious to do as a programmer, making a simple dice roll is far far easier) then I would probably look at any drop rate cheats first of all and work backwards from there. If there is some kind of drop rate modifier for a quest or area, or pickup then that too might be interesting to see what goes for it.