I picked up mechanic skills specifically since there wasn't one on the ship at the time, but I could change that to some other viable cover occupation.
Edit: I sent a revised Gabe Vin's way. He's got a more prestigious cover occupation that I hope you'll like a bit more, Slippers. ^.^
It could of course go the other way – he started out life as a ship’s mechanic, but a passing Companion took note of his natural charms, and referred him for training to join their ranks. It’d explain why he’s handy with repairs, notwithstanding the prospects of a more illustrious career at his fingertips. Just a thought, of course; the character is yours, and nobody else's.
As for the lack of mechanic... there’s no rule saying we must
have all archetypal roles fulfilled, and admittedly there’s an argument for having an atypical crew rather than one that ticks all the figurative boxes… but it all comes down to what people want to play. Generally speaking, playing a unique role (the ship’s mechanic) is going to be a lot more fun than playing a redundant one (the other other