>>56234396She could know 5 steel moves in total, not 3 in gen 8
Also back in gen 3, there were barely any steel moves and most didn't make sense to be on Mawile, there's no reason for her to know iron head, steel wing. Doom desire and meteor mash were signature moves for Jirachi and Metagross respectively.
At the time, iron defense was the only one that made sense, the only two you could make an argument for are metal claw and maybe metal sound.
Later on she did gain access to iron head, metal burst, flash cannon (no idea why), and steel beam when those moves were introduced
Also, can be based on bear traps as well
