Serial number now on the back side.

During World War II, the Soviet camera maker FED had to evacuate its plant to escape advancing German troops. After the war FED had trouble getting its copy of the pre-war German Leica 35mm camera back into production. Because KMZ's plant near Moscow had escaped destruction, that company started making the FED camera under a joint FED-Zorki logo. When FED got back in operation, KMZ continued to produce the cameras under the Zorki trademark and made some design changes. The Zorki 1 was not synchronized for flash, however, some cameras have that feature - apparently added later by their owners (source: http://home.att.net/~wayne.cornell/camera/zorki12list.html).