Based on your and Johnans comments, I was still not comfortable with what I was seeing in this rifle. It seemed "hinky". You guys are correct that 1864 rifles were sold as surplus and modified thereafter in a number of ways.
I took the photos I had (I did not post all of them) and went to the Springfield Armory Museum today. It is now run by the NPS. A met a ranger who had great knowledge of these weapons. My photos were not the best (Thank u Samsung), yet, even w/ the pics I had the ranger could tell there were many modifications to this rifle - u could not say it was simply a 1886 Trapdoor. From what I recall, he said the rifle had been cut down - the barrel was not as long as it should be. One of the rings is missing and the front one was is jury rigged to an arbitrary place. The receiver for the sling is incorrect (jury rigged) and the sling itself is not authentic. The maker marks on the barrel are either absent or covered by the new Trapdoor hardware. The stock itself was "rounded" in several places where it had sharp edges in the 1864 and 1866 incarnations. He showed me more rifles and said the one I had pics of was closer to or had many features of the, I think 1886 trapdoor.
The rifle is most likely a sport conversion which incorporates many parts, some of which may be unique. I was hoping to buy a rifle which had the chance of being in the civil war - he got a kick out of that and asked me if I was going to pursue this. I said no and he thought that was a pretty good idea.
PS - I have visited this armory 3 times now. I typically carve time out of my work day to go, when I am in the area. One could never assimilate all the material (artifacts, publications and video), in 6 months never mind of few hours. The ranger today showed me a Springfield that was recovered from an indian after Little Big Horn and said that they had forensic proof that the rifle was used at LBH based on ballistic analysis of bullets found at the site. I think that is pretty impressive.
Thank you all for your help and responses.