Has anyone seen a gun like this?

I was at the Gunshow and bought this handgun.
It’s clearly a percussion black powder pistol. I’ve never seen this kind of frame on a BP pistol before. No markings or serial numbers. Some stamped engravings on the frame of a gentleman in a suit and hat in a dueling stance. The barrel appears to be 45 caliber and a take off from a rifle because it still has a raised rear sight with notches to 1000 yards. The seller knew nothing to add. Any thoughts would be appreciated