This is the Leica II with the correct lens cap shown. (Or rather one just like one shown in a photograph of a IIIa in a 1941 magazine article about the FED I saying what a good clone it was of the Leica II and showing them both. The IIIa can be dated very easily to 1935 - 39, although a handful were made in 1947/48.)
Look dead centre of this picture and you can see "1,25" meaning 1·25 metres (about 4'. 2") on the distance scale and note that it is the right way up. On the USSR made Industar lenses the figures will be upside-down. Often FED lenses are re-engraved at the front to look like Leica ones but the fakers don't seem to bother with the 1.25 mark.
Note also the little notch, top right hand corner, to the view-finder window, which is between the two little round windows of the range-finder. And there's four blackened screws hidden in the black body cover of this Leica that will usually be bright, shiny chrome plated on the Zorki and FED versions..