Seeing the rest of this rifle will help us understand the nose cap. If the maker was a good builder, as it appears from what little we can see around the rear ramrod pipe, I'd question whether this is the original cast pewter nose cap. Most good, old time builders would not accept such a rough nose cap on one of their rifles. Their reputation was their most important marketing tool back in those days. Two possibilities come to mind. This may be a shortened full-stocked rifle where the nose cap was cast later in the rifle's life, perhaps trying to duplicate the original nose cap but by a less talented hand that created a "somewhat similar" nose cap of lesser workmanship, but too crude around the edges to be the original gunmaker's work. Another possible factor is the quality of the pewter, i.e., tin and lead. This cap may have a higher lead content, leading to a duller, softer, more easily damaged nose cap, a less sharp casting, and more prone to oxidation... which again would suggest a lesser skilled gunsmith and perhaps a later nose cap.
The nose cap appears to be a Tennessee style cast pewter cap, but the quality does not appear to match the quality of the rifle, raising questions about its originality: is it a later cap for a shortened rifle, is it a replacement nose cap for a damaged original cap, etc. If the rest of the rifle appears well-made, I doubt this is its original nose cap, although it was probably put on the gun in Tennessee. If the rest of the rifle is somewhat rough, or crude, in original workmanship [not later damage], then perhaps the current nose cap is original, because it then better matches the workmanship on the rest of the gun.
Shelby Gallien