I recently brought home my grandfathers 1898 Krag from my father's home. I used this gun for Elk hunting in Montana as a boy. I need information on how best to disassemble, clean and inspect it to make sure it is still suitable to shoot. Any information about this gun would be welcome. The serial number is 98829. Pictures are attached. There is a mounting hole (?) about 1 1/2 inch in front of the rear sight. Is the rear sight original? I will add a number of photos. Thanks