I don't think rear sights were common on a smoothbore, but I'm not an expert.
I think 1855 is a little late for this piece.
It appears to be an everyday work gun, not a special piece for someone who appreciated flintlocks. I would think that a man buying a regular gun would want the most reliable he could afford. I feel cap and ball would be the pick, unless
this fowler was much cheaper than a C & B. But, what do I know?
It's seen quite a bit of use, as you can see, the frizzen was "resoled". Another piece of steel was soldered on the face.
Well, thanks for your time and help.
Jerry