anglaispierre.... I still can't envision the pins that you are talking about. The "pin" that stops the cylinder from turning is actually a rectangular looking piece of metal that rises from the bottom of the frame to engage the rectangular cuts in the side of the cylinder.... it is called a "bolt" and is #12 in this diagram. (The diagram is actually an 1851 Navy but the mechanics are pretty much the same.)
The cylinder pins I was originally referencing are #41.
Which pins do you mean?
Oops, just went back to your original post and noticed you had said "barrel locking pins". Those would be #23 in the diagram. If nothing else you could make them yourself out of a proper diameter nail. Glue in place with Loc-Tite or epoxy.