We need to see pictures! "Model 1870" would NOT normally appear on a Model 1869 cadet rifle, which this seems to be.
This is one of those truly frustrating threads. The original poster has, despite several requests, never had the courtesy to post pictures. Along the way, he has been given advice ranging from ludicrous to quite accurate. He MIGHT have one of the 20 (yes 20!) M1869 Cadets assembled by SA long after the model had been discontinued, and whose true features are in some doubt, even among the experts. It would be nice to know, but, I suspect we never will.