the make a reproduction spencer. fun to shoot, and your not messing with an piece of history. and didn't realize they made them pre war. must be a very early gun.
http://www.cimarron-firearms.com/RepeatingRifles/Spencer.htm
most civil war weapons were cranked out by the hundreds of thousands. and not worth as much as you'd think. but any repeater is very desirable.
if you can tie the gun to an individual soldier or battle, that will instantly double the value.