The lightly engraved/scratched "JMK 1884" on the cap box is not done in the gunmaker's hand, and is a later addition by an owner. The maker of the rifle would have signed or initialed the barrel, so if the traces of engraving on the barrel, amid the surface scratching, can be figured out, the maker can probably be identified.
The rifle appears to have nice lines, and could be a WV gun. But these somewhat later percussion rifles don't have as many identifying details as earlier guns, and are more difficult to figure out. When a gun has changed hands several times over the course of its life, it becomes more difficult to pin it down since we don't really know if it came from the last state it resided in, or one near by. Those markings on the barrel are the key to figuring out this rifle...if we can somehow decipher them. Shelby Gallien