I'm sure it's fake.
The camera in question does not have decorative rims along the edges of the vulcanite, and it has the old style, non-threaded shutter release. Then it has the new-style big-typeface shutter speed engravings. This places the manufacturing date in 1949 - if it is indeed a Zorki, and not a FED to start with, as I'd suspect from the shiny top of the shutter release button (a matching FED would be from the same era, however, older than 1953 with this type of shutter release).
The lens also is much more likely of FED origin. This type of aperture setting lever was replaced on Zorki's Industar-22 lenses with a ring beginning in 1949. Only few, old-style lever samples of the Industar-22 exist, and these would be highly collectible in their own right.
With all real soviet commemorative cameras, they did put normal lenses on. They did not have any commemorative cameras where the lenses were different or re-engraved with different names, let alone serial nos. from normal models - all the engravings or screen prints were on the camera bodies or in some instances even only the box was different.
Also, I'm not aware of any commemorative version of any soviet camera which does not show the camera's make or model. They all have additional engravings or print
beside the normal FED or Zorki Logo. On these Jura fakes, the original factory engravings are always completely replaced.
At the time when this camera left the factory, even Sputnik-1's launch was still science fiction for years to come, leave alone Gagarin's.
I don't believe they'd have made commemorative cameras for such an important event in 1961 from stuff that had been obsolete for 12 years by then. This makes no sense.
If you look at this italian guy's Jura Zorki (scroll down), it's quite different from the one in the ebay auction:
http://corsopolaris.net/supercameras/LeicaCopy/Zorki/zorki.html
Much more modern, but also not latest version of Zorki-1, with matching lens (see focusing knob). It has at least a KMZ logo on top. The engravings are much finer, and they are not filled with red ink as with the ebay sample.
Why would they make different versions of engravings, based on differently old versions of an obsolete camera model that has been out of production for minimum 6 years at the time? No, I don't believe these are authentic.
W