You have found yourself a really North East fowler. It appears to be a 1700s gun and is in very nice condition. It was probably made in MA, but that isn't necessarily the case since all of the New England colonies (states) made similar pieces.
The lock appears to be a flat face English piece with late colonial engraving. I note that a hole in the plate, behind the pan, appears to have been filled in recently. Makes me wonder if the lock is original to the gun? It certainly looks good. Wonder too whether it has been reconverted, though I doubt that it has.
Stock wood looks like cherry and is quite sound for its age. It is interesting, too that the gun is set up for a sling having the triggerguard drilled for a swivel. There are many similarities with the Abner Howe NE gun (in the Library). The guards are, engraving is similar and the architecture is close but not the same. Could be the same maker for both or somehow related in time and/or area.
Your fowler looks like it may have a 48-50 inch barrel; is there a bayonet stud near the muzzle, a sight blade?
Wonder, too, if there are any initials on the gun? The view of the top of the barrel is too indistinct to tell if there is anything on it.
Thank you for showing it around. It looks great over your fireplace, but you gotta lose those African spears.
Thanks-Dick