Re: Gunsmith for full build
I own Thoroughbred Rifles LLC and we build full custom rifles on our own receiver that is manufactured for us to our spec by Stiller Precision. We have our model name (Thoroughbred), our company name and location (Thoroughbred Rifles LLC, Frisco, TX) and the serial number on the left side of the action just like every other manufacturer is required to do (Remington, Winchester, Browning, Sako, Weatherby, etc). I think you are probably referring to stamping the barrel which many gunsmiths do when they do a build from components as required by the BATF rules.
I've seen Jim See's work and would highly recommend him for assembling a custom build with your components. Really good guy.