I have a Zorki-4 s/n 5639968 made in 1956. This camera has some details that are different from later ones. Is this the earliest Zorki-4 model? I think it shared some parts such as winding and rewinding nobs with that of Zorki-3C.Here is an image FYI.
Kind Regards,
Zhang
http://www.ussrphoto.com/UserContent/11122009_IMG_8937.JPG
