This rifle looks very much like a late 1850s gun, based on its late style guard, butt curvature with pointed toe, butt height, etc. I do not believe the gun was ever flint, but rather made as a late percussion rifle. The "cut" you see above the hammer is split off perfectly with the grain on the back end, and is very flat to the rear. This lost wood is simply where a piece of wood chipped out of the side facing, following the wood's grain. If it were a flint **** cut, it would be a lot more worn and not precisely running with the wood grain. A photograph from above, showing the tang and wood [or missing wood] on either side of the tang, would resolve this issue quickly. The percussion lock is not sitting properly in its old mortise for a reason. If you look closely, the mortise appears made for this lock, but unfortunately the wood just above the nose of the lock that holds the lock in place, has broken out, allowing the main spring to force the nose of the lock upward and partially out of its old mortise. Put the hammer at half-**** so its off the nipple, and I bet the lock will drop back into the old mortise nicely.
This is a good example of a lower cost "working rifle" that most average farmers would have, a good shooting rifle without the fancy details. These plainer rifles are hard to identify when not signed, since they lack so many distinctive details of the fancier rifles that more clearly show the gunmaker's work, or hand. If the rifle is to be identified, it would have to have traces of the maker's initials or name on the top barrel flat several inches behind the rear sight. Its stocking looks correct for southwestern VA. Shelby Gallien