To answer a question posted above about the two open holes in the barrel tang. This is another curious mystery. There are no threads in the two holes. And, there are no holes beneath the tang in the stock where wood screws or nails would have been. So the only thing holding the barrel to the stock are the multiple barrel bands, which do hold it firmly in place. My guess is that the were originally screws/nails used when the barrel was originally utilized as a matchlock. So the barrel was re-used while making the current stock and flintlock configuration.
I do have some original dome head wood screws that are over 125 years old that I thought about using.

Rick.