Hi,
Remember, most gunsmiths in the past used barrels and locks manufactured by barrel and lock making specialists and often imported hardware. It was largely an economic decision because those components were cheaper than made by the smith. The film "Gunsmith of Williamsburg" describes scratch building that was not the norm particularly during colonial times. I am sure apprentices in America likely learned those skills but then hopefully ignored barrel making as much as they could for the rest of their careers. Today, there is no need to make barrels. Modern barrels are safer and there is a good variety to choose from. Although I understand the barrel making process, I probably never will make one from scratch because you can't do it alone and it is not a skill set that I consider necessary to call yourself a muzzleloading gunsmith, which I unconditionally call myself. Nor do I believe you need to be able to make a lock from scratch to call yourself a gunsmith. However, I do believe you need to be able to make every part, fix locks, tune locks, modify locks to fit objectives, and make springs. I also believe there is a minimum skill set required to advertise yourself as a muzzleloading gunsmith. In my opinion, you should be able to breech barrels, crown muzzles, make and install lugs and sights, install vent hole liners, make and modify all hardware to suit objectives if required. You need to be able to not only make stocks from scratch but give them good architecture and details. Furthermore, if you advertise your work as historically correct, you need to be historically correct, which means you better know the styles and history of what you portray. If all you do is casual internet browsing, your knowledge will be superficial, indeed. Anyway, it is fine to just assemble kits, or finish guns in the white. I am happy to see folks assembling kits, like Kiblers and Chambers, and selling them. Not everyone needs to be a "muzzleloading gunsmith" and there is plenty of room for everyone to find their place. The only time my hackles rise is when somebody portrays themselves as something they are not.
dave