When did the FED f3.5 / 50mm changed f18 for f16

Hi, my first Soviet camera was a FED-1 (d), I presume made in 1939. But I have noticed that the lens, a FED f3.5 / 50mm has a maximum aperture of f16, but it seems that by that time the proper type of FED lens should have f18 as maximum aperture. Is that right? And when did that change happened?

Thanks in advance!

Hi, the change was after 2nd WW. So your FED should have old aperture scale ending with f/18.

To be more precise (just a bit!), the aperture scale changed near the end of the 1f, 1st version, s/n c. 280000/300000, so probably in 1951.
Alfa is right,; a correct lens would be better for collection (if not to shoot!).

Amitiйs. Jacques.