A Leica II, Zorki 1 and a FED 1
These cameras are all very similar and there are a lot of fake Leicas about based on the former USSR cameras. Some are quite dreadful and are black or chrome and covered with swastikas to make out that they were Third Reich (Nazi) Government issue.
Here's all three head on to show how very similar they are. A quick check on the lens would be to see if it says 5cm or 50m/m. Another quick check is the four screws; black chrome on the Leica and shiny chrome on the FED and Zorki. And do look at the baseplate, Photo 22 further on.
The Leica's a model II from the mid 1930's and it was copied by the USSR as the FED 1. The FED version shown at the bottom of the photo is a 1950 or 51 version when they were still very similar to the model II Leica. Even the aperture scale was marked with the old "German" values and runs f/3·5 - f/4·5 - f/6·3 - f/9 - f/12·5 and f/18. Actually it's f/6,3 etc with a comma instead of a decimal point. A point in favour of the USSR version is that the lens will usually be coated (being generally post 1946-ish) but the Leica "Elmar" won't usually be - well, not if it's a 1930's one.
The shutter speeds went Z - 20 - 30 - 40 - 60 - 100 - 200 and 500 and so are off-scale and odd if not difficult to use. "Z" was for "bulb". Oddly enough the USSR ones have "Z" for bulb but that letter does not exist in the Cyrillic alphabet...
In 1938 or 39 a version of the FED appeared with a top speed of 1/,000th of a second. They are rare and expensive.
The Zorki 1 is a little later (about 1953) and has the modern standardised apertures marked (f/3·5 then f/4 etc). It also has the "lavatory pan" shutter button surround, unlike the other two. And the lens is labelled "Industar-22" but the FED's ones were just marked FED and were Industar 10's.
FWIW, I have used the Industar-10 from one of my FED 1's in my Leica M2 and it performed very well.
Beware, these cameras are addictive; learn from my experience.
You may not see it but it is blindingly obvious to me that the lens cap with the Leica is the wrong vintage. Tracing a 30's or 40's picture of the camera with a lens cap cost a lot of time and money just to get a copy of an elderly magazine with a picture of the cap and the f/2 lens. But the one on the camera is the f/3·5 Elmar... Getting the lens cap was simply a question of digging deep into my pocket. Then I wondered if they made both styles as the FED may be a copy of the 30's one or a modern one. And so it goes on and on.
There are two periods for FED's; they started in the mid 1930's but the factory was overrun by the Germans in 1941. The second version was made from 1946 or so in the rebuilt factory.
KMZ started to make their version (the Zorki 1) from 1949.
Leica FED Zorki and Fakes