Hand tools are fine, but I don't think even a beginner can get by without a decent drill press and lathe. And knowing how to use them, which gets into the question of learning machine work.
Knowing gun design is pretty important, too. I have seen a couple of cases where a gunsmith drilling a Mauser action drilled right into the chamber because he didn't know where the chamber was in relation to the receiver ring. Another never heard of short chambering, so when he installed a new barrel, he ground the back end of the locking lugs so the round would chamber. Others have tried to drill for a scope using a hand drill, with, shall we say, less than optimum results. One "expert" on the M1911 pistol got so tired of his knife edge sears failing from the hammer falling into the half-cock notch that he ground off the half-cock notch. Yup - machine gun!
I do have a bit of a problem when I realize that to be a beautician requires a series of courses, certified training, an intensive examination, and a state license, where to be a gunsmith requires nothing but an FFL (which says nothing about the holder's competence) and a sign on the door.