Hello, my grandfather just gave me his old spencer carbine. I was doing research online and stumbled across this forum and wanted to know if any one could help. I will include pictures as well but it is a M1860 Carbine SN: 3131. With my research I have seen that the Carbine SN shouldn't start until 11000 but the SN matches on both the lower and the barrel. Plus there are multiple markings on the barrel, one marking is.... F C I and the other marking is.... CO A. Any information will help.