The 2 top gunsmithing trade schools/programs Im aware of are in CO & in metro Pittsburgh PA. The PA training program is called the PA School of Gunsmithing. I think.
The other class in CO(near Denver I think) is also considered worth the $$$ or time. Bill Lauthridge, of www.Cylinder-slide.com
offers professional level skill training & classes.
For handguns & pistolsmithing, I'd consider the www.AmericanPistol.com
site. The members or guild may guide you in finding the best course or school.
If I recall; the former gunsmith/shop exec: Vince from Discovery's popular Sons of Guns
unscripted show said he went to the PA gunsmithing program in Pittsburgh.
I lived in Pittsburgh from 1995-2000 & considered using my GI Bill $ to become a professional gunsmith(pistolsmith).