Your additional pictures are good and clear. The long "two-screw" tang is a southern detail, but I have not seen this exact shape before, where the edges are beveled for about the last half of its length... a neat detail. The large, hexagonal side lug for the percussion nipple is also rather unique. This rifle, without a signed barrel [at least I can't see anything there] will be difficult to locate accurately.
I think the long tang with two screws really makes it a "southern" rifle, but that doesn't narrow it down much. My best guess, based on the pointed side facings, long 2-screw tang, walnut stock with very straight comb and toe lines, and abrupt break where comb meets wrist, is that this rifle is most likely a product of the Appalachian "hill country" area where western NC, southeastern KY, and northeast TN converge. I'd also think, based on the small size and shallow "beaver tail" shape of the cheekpiece, and the thinness of the butt with long heel extension, that the rifle may be a little later than I originally thought, perhaps the 1860s. It's a nice, clean rifle with some interesting details, and hopefully a similar rifle with a name or initials on the barrel will show up in the future to help us identify this one. Perhaps another member here has seen a similar rifle or can provide more insight into this rifle.
Shelby Gallien