I agree the triggerguard is probably a replacement, why else would that 1/4" gap be at the toe of it? More important clue - the butt molding line was carved
before the triggerguard was put on. It's inlet actually overruns and ruins that line, in places on the side. (click buttstock photo for larger). No gunsmith making a fresh rifle would have carved that line, then destroyed it to install a triggerguard toe.
Also, the hammer was replaced, and likely the lock. What I'm surmising is this was a simple rifle made for someone cheaply. Later, maybe further on the frontier, the owner and settler had the triggerguard replaced when broken, then later converted the rifle to percussion. There is no buttplate, the key indicator of an economy model by a gunsmith that may have be able to add one if requested. The carvings are simple but well done. The buttstock molding line and forend are well done. The stock archtecture is nice, thin and the cheekpiece is wll let down on the side of the stock.
I would guess the rifle was made by a somewhat skilled gunsmith out on the frontier after the Wilderness Road was built. Maybe 20 years after settlers started using it, they still needed rifles and would want one cheaper than a fancy norther Virginia or Pennsylvania rifle. The gunsmith may have watched his father or uncle build them as he was growing up in the first decade of the 1800s, who learned further north, and just followed his lead to make this one.
I've taken the liberty to right the photos to the view we are most used to seeing:
