Need information on a Navy Arms commemorative

I have a Mod. 1866 Navy Arms rifle that I need some information on. The rifle has a brass frame with "1876 to 1976" and "To commemorate the Indian victory at the little Big Horn June 25 1876" ingraved on the right loading gate side,and an Indian chief head ingraved on the left side with silver studs on the forearm and stock. Also on the rear tang behind the hammer is the numbers 9xx of 1500. Any information on the name of the comm. or worth of it would be appreciated.