Dave Pernell (a member here) was making firing pins, you may want to check with him.
for stock work - you may be thinking of Brad Bachelder you also may want to talk to Brian Dudley (also a member here) his work has gotten praise from other members
Hammers, good luck - you may look for a set as easily as finding one to match, neither is going to be an easy search.
Tom Carter (also a member here - notice a pattern developing
) is making hammer screws when you get to that point.
becoming a member will allow you to post want to buy ads the will be seen by the most knowledgeable Parker folks you can find.
the project will not be inexpensive, but if the barrel are safe, bringing one back from the dead can be very satisfying