I think it is even easier to understand current practices. Look at the firms' factories and staffing. Look at the firms supporting apprenticeship programs and one can intuit where the shortages of craftsmen are... By definition, this is the legacy of participation in two devastating world wars.
I have found most staff will be pleased to discuss what is to be done in their factory as well as how limited the number of guns they produce in any year might be. Also, if I want the engraving, choking, inlay, or whatnot done by a particular master, that can be arranged if it isn't already based on my tastes. Ultimately, the marque on the gun will be supported by the lengths to which the firm went to produce each particular piece to the highest standards.
