That's looks just a like the one for sale....(not sure if it has a case most likely does) ......they look like a muzzle loader with a hinged stock....the wood is darkened more on the one the guy has for sale he imported it out of England looks untouched by the hands of man since manufacture....except for his importers mark.
Most pin fires I ran across were in good condition what that tells me they weren't used much...you could speculate on why.

I think it's most likely they were left in the dust by the centerfires.