I've had a lot of discussions with the current owner who has been very generous in sharing it, about its origins and have handled it a couple times. Its origin is a conundrum to me because the slight stepped wrist steers me in one direction, and other features steer me in another. The amount of wear on the tang carving obscures the original form somewhat, which is not helpful. The barrel is a replacement and some of the forestock is a restoration. The lock may be the second lock on the gun as it seems more recent than the rest of the gun.
The signatures which I think may offer clues to origin:
The cheekpiece has a form which seems to me to be similar to that on the great Newcomer rifle, the Peter Resor "ghost" rifle, and some Schroyer-attributed rifles. The cheekpiece is also very prominent and bulges out dramatically like some Berks county guns.
The carving has unusual tendril terminations like the great Newcomer rifle, a couple Schroyer-attributed rifles, and the Peter Resor ghost rifle.
The guard is a bit of a conundrum. Most of it except the spur is similar to that on RCA124, a Southern walnut-stocked rifle out of Virginia.
The sideplate offers little help.