This one was used during it's working lifetime, which is a good look. You can see the sight is a new one, the original longer sight was gone, and someone replaced it with this simpler and more robust sight.
For my taste, I like it better with the new one removed, since you are not going to be shooting this and so don't need a rear sight.
These Spencer carbines were well liked, and there was a continuing demand for them even after the War. They were used in the West...In the Clint Eastwood moving "Unforgiven" the character Ned Logan played by Morgan Freeman was using his Spencer Carbine as his weapon of choice....I think this movie was set about 1881.