Question

Well you know how kelceon can chage types based off of the moves it gets hit by. Well if it gets hit by Flamethrower and change to a fire type, will it get STAB if it used flamethrower itself?

Answer 1

Yes it can, because stab means Same Type Attack Bonus so of course.

EDIT: http://pokemondb.net/pokebase/56277/does-kecleon-stab-from-moves-changes-type-move-that-already

yes it does it gets stab from its current type so in theory kekleon can get stab from any move that deels damage that it can know but that is considering it has changed type
i think it works a bit like hidden power of the same type