I have just acquired an 1863 Sharps Carbine - still percussion. I have found some initials on the gun that I would like to find their meaning. Can someone help me? On the saddle ring fastener there is "J.H.G." On the left side of the barrel under the barrel band is "R". On the bottom of the barrel and under the forearm is "Z". The serial number is: 997** and it is still a .52 caliber. Thanks for the help.