That is a very interesting rifle. I had that one bookmarked, although I did not bid; you made a very good buy. It has been well looked after, I hope the bore is as good as the exterior. There were a number of interesting pieces in Paul's auction. He is attracting quality pieces. Told me about 70% of his sales on on-line. I live about 70 minutes from him, and make a point of looking at pieces when dropping off guns for sale. Had four in this sale, and am very pleased with the return. In this forum, I have started a thread about the W&C Ogden combination gun. It is the one in the sale, picked it up yesterday.
If you look at the tang, you can see where a different aperture sight was mounted. I suspect that was the original, when the piece was still flint, the current sight being added when the rifle was being used in percussion.