PA?MER ELLIOTT & Co. was the company that made the lock, the gun itself was likely handmade. Is it possible to make more photographs? A view of the off lock side and the everything behind the lock including the cheek piece, if any. Details of the entry cap (where the ramrod enters the stock), the trigger guard, sights, muzzle, and any other markings. The gun looks in good condition for its age. There might be a signature on the bottom of the barrel, have you ever had the gun apart?
dave