Coffinmaker,
Maynard became very well known for the accuracy of their .40 and .44 cal. target Rifle.
It is my belief that this 26" barreled 1865 model Sporting percussion firearm was set up, scope included, as a demo type gun for mid and long range target shooting.
It not only had the scope, but also had the venier tang sight (which could not be used with the scope attached).
I did not post this info on the Henry forum because I had a Maynard. I posted it here because of the scope and that this type of scope is contemperary to the one pictured in the OP.
My best,
Blair