Where can you find the rear peep sight for a Stevens model 56?

Try Bob's Gun Shop... http://www.gun-parts.com/savagerifle/

I have not orderded any parts yet from them, but they seem to have quite a selection of parts for the savage and springfield Stevens rifles. I recently was handed a model 56 less the peep site, buck horn and 5 round clip. The gun's not worth much, but it seems like a fun project.