Southern rifles seem to be a group of guns where everyone knows a little about them, but experts on them are usually limited to certain areas and not broad-based. There is often a lot of speculation on "different looking" southern guns based on what we know about northern guns... which often doesn't hold true for southern guns... especially when we realize with more rural or backwoods guns, styles changed more slowly and guns often look a bit earlier than they really are. This gun looks like it was a "poor boy" from the beginning, without butt plate, nose cap, and rear pipe. I've seen similar excessive wear on several rifles including a couple from Kentucky and western North Carolina, indicating a hard life [since it was considered a tool rather than show piece] with much more use/activity than many finer northern guns. I'd guess the carving was added later by the owner, perhaps after seeing a better carved gun and wanting to enhance his own gun beyond its basic "tool" identity.
One of my pet peeves on many dated/attributed rifles such as this one, is the failure of the attributer to explain WHY he attributed and dated it as he did. When I look at this rifle, I see significant butt drop for a gun dated as early as this one. I'd like to see the thickness of the butt, which also may not support such an early date... and the butt cavity looks pretty shallow in this gun suggesting a moderate butt width. The cheek seems to be hollowed, or concave [perhaps it's the lighting], and if so, may help locate the gun toward the Carolinas.
I think at times when we see an unknown gun, we get a first impression of it and sometimes make it become what we wish it was, when we really don't know. The lock even raises a question in my mind. The two visible screw heads appear to have machine-cut, flat bottom slots, rather than chisel-cut "V" slots like on early guns. The cock's jaw screw looks new to me, and I would have expected a bit larger, more rounded [no "rooster neck"] cock if the gun were as early as claimed. The lock plate has uneven rusting, with areas of surface that remain relatively smooth... not sure how that could be, if the gun were really that old, and really saw enough rough backwoods service to wear the heel down that heavily.
Interesting gun, looks southern, but not well understood at this time, so becomes questionable when we begin to pigeon-hole it too tightly.
Shelby Gallien