As I recall, there were (are) a lot of them without any patchbox at all but I would think if the rifle is a Caplock, a small oval patchbox would work.
Companys like Tryon and others were selling these patchboxes (Capboxes) by mail order thruout the middle and late 1800s.
At the risk of being wrong, I think the folks in the Tennessee region pretty much had their rifles made with the extras they liked and that they could afford to buy.
My comment could explain why we see guns without even a butt plate on up to some that were moderately fancy.