For someone who studies early Kentucky [state] guns, you have a fascinating rifle. The signature is great, and the earliest one I've seen. The side plate is also correct, but longer than any I've seen, again suggesting an early Jones rifle. It also has a little straighter stock architecture, expected of an earlier rifle by Jones. I have never seen that style front "hair" trigger on any KY gun, with the adjustment screw forward of the front trigger in the Virginia Sheets gunsmiths' style. It looks good, but very unexpected on an Ohio River gun from the southern shore.
The lock itself looks good, but its size is larger than most locks used on Kentucky guns. Jones worked close to the Sells, Michael of Augusta in Bracken County and Benjamin [trained by Michael] just across the river in Brown County, Ohio, and their guns share some similarities with Jones' work. Most guns from that era and area leave more wood in the side facing in front of, and behind, the lock. While the lock may well be original to the gun, I would want to take a closer look at the front side facing itself, and inside the open lock mortise, before I would be comfortable accepting the lock as original to the gun. This slight uneasiness with the larger lock size and being flint in this era, is tweaked by seeing signs of prior expert restoration on the gun [above front nose of lock] and recoloring. It would be neat to really handle this rifle and understand it better, because, regardless of my comments, it's the earliest A. J. Jones rifle that I have seen, has the best stock lines [expected of an earlier gun], and is a great looking Kentucky gun. Thank you for posting the pictures.
Shelby Gallien