It appears to be British proofed, Birmingham as has been stated, it looks like the 1855-1875 proofs. Note the 14 though, that means “14 bore,” at the time the British only marked the bore, not the chamber, that could well be a 14 gauge (brass is available but it is horendously expensive), but it could also be a 12. During that era the Brits made some 12 gauges with 14 gauge bores, I’m not sure why, but possibly cost saving If I were to guess, or maybe they thought that it was better somehow. Basicly think of it like a modified choke except it is the full length of the bore, which is actually cylinder. More than likely it has a laminated or Damascus barrel as well (probably laminated).
It is not designed for smokeless, black powder only, and since it is a tight bore I would suggest going with light loads.
Who made the locks? It should be engraved on the lock plates. I’m going to go out on a limb and guess W. Richards?
The previous poster was correct that the refinish killed the value. In general you only want to do a refinish if necessary, basically if the old one is a (likely unfireable) mess or a previous refinish job was job was done, and if it is very rare it shouldn’t even be done then.
The maker determines the value.