I'm not the best scholar to answer your inquiry but since 174 views with zero replies have passed, I'll say something about it.
First of all you say "nice early guns". What are you calling "early"?
As I understand it there was much more "in-house" making of furnishings in the early years, and that it would be much more likely for gunmakers to rely on outsourced parts in the later period of flintlock production which overlapped capper guns-when I would expect more outsourcing was done than in the early years.
Maybe that'll be enough to get the folks who have indeed studied these things to chime in. And if those gentlemen/ladies find my vague assessment here inaccurate, unsupported, or misleading, I'll bow out to them and adjust my thinking.