After viewing your pictures of this rifle I just have to comment. First off, more pictures are needed of the lock close up.
I will share a bit of my background before giving you my opinion. I have been a collector, builder, and student of the Pennsylvania Kentucky rifle for over 25 years. I have owned several originals from many "schools" including western PA to the Lehigh Valley.
IMHO, your pictured rifle is an old piece that has been extensively "worked on" in modern times. The cheek side incised carving looks to be the work of a complete novice with not much knowledge or skill. The depth and lack of ware of said carving is also a clue as to its more recent birth.
If I were you Oldyellerdawg, I'd pass on this rifle and save yourself a lot of hard knocks education! Whoever is trying to pass this gun off as being totally original is either a crook or just plain unknowing of just what it represents. If you are looking for a nice longrifle to shoot, your money would be best spent on a custom piece available here on these forums.
Just sharing my experienced honest opinion here. Good luck to you sir, Joel