I managed to find another vintage rangefinder, or is it? This one is a FED-5V designed in the 1970s. However it has a very late serial number and may well be one of the last models built in the mid-1990s.
Anyway, it all works mechanically and the rangefinder appears to be accurate. So I'm running a film through it to see whether it is light tight and whether the lens is functioning well. I'll post my progress here.