01 FFL and very successful home base 'Smithing business for 13 years here.
Strictly a Smithing business, no sales or transfers conducted at all.
Not formally "trained' in a school, have worked on firearms for over 40 years, formal back ground as a machinist.
IMHO the schooling aspect is not overly critical. From what I have seen of the average Smithing school graduate has a basic fundamental knowledge of general gunsmithing operations. It qualifies one for an entry level job in the industry. Heck, I have dealt with grads of one of the highly rated schools and they did not learn a damn thing about the Kalishnakov nor AR family of firearms. Boy but they could sure do a polished blue.
IMHO that is not overly practical in todays market.
You can get a copy of Roy Dunlaps "Gunsmithing" and have the course curriculum for most schools for $30.00.
I think what is more critical is ones aptitude and knack for the little machines we deal with.