I think your gun originally came from Ohio, not Pennsylvania. The mountings are from a high-quality James Teaff rifle made at Steubenville in Jefferson County, Ohio. The patchbox finial is a little different from his normal Ohio "National Road" style finial, but the fine engraving on the box's side leaves and the fancy side plate opposite the lock are very typical of his work. The guard looks more like guards used by his son Nimrod, but again, the fine engraving, patchbox side leaves, and fancy outline of the side plate strongly suggest the original gun was the work of James Teaff.
Shelby Gallien