First off, does the venomoth know silver wind from lv 1 of?
i tried a lv 1 dungeon yesterday (joyous tower, or something), and when i got inside, all pokemons were setted down to lv 1, as it says in the description.
now listen:
my sceptile had:
giga drain
slam
brick break
solar beam (lol, using it against bosses

).
when i came in there, it had:
absorb
pound
leer
<some thing low lv i cant remember lol).
so, its moves gets put down to the 4 earliest it's learning.