I have always been under the impression that the lockmaker supplied the completed lock, and all the gunmaker had to do was inlet it into the stock in the proper position. He probably had to caseharden the lockplate to his specs, but I have understood that the lock supplied was a perfectly working, completely functional lock.

I'd be very interested to learn if it was different from this.

All my best, SRH

May God bless America and those who defend her.