Many Thanks to the both of you - "pop", that's a nice bit of info for a load. Lagopus, this guy is a real mystery man. Apparently, or should I say supposedly, he sold "trade guns" to American Indians in the Pacific Northwest. PeteM got ahold of the most information I've seen - The Chance name/company went through many incarnations, the last being W.Chance Co. which is on my piece. Prior to that it was W. Chance & Sons.
Interesting bit about William Bishop's name and "address" making the pouch more valuable. I just can't make the connection, which is even harder to research than W.Chance guns!