Hi Alexander, No real explanation to propose... I have too a pre war Fed lens without number. Perhaps an omission? A "communard" who put the lens in his pocket before it was numbered?
Amitiés. Jacques. PS: as you know, the serial number should be 4xxxx.
<quote>A "communard" who put the lens in his pocket before it was numbered?</quote> I like this explanation Very much possible. Brave Communar ! He/She most likely be kill if caught
Honestly I just think that at that point in time when all these early lenses were produced the production has not been very strict in terms of process and I don't think they cared much if one or two lenses got skipped on engraving the number.. I tend to agree with Jacques that it's just simply an omission due to lack of strict assembly line rules.. those were kids after all as mind boggling as it seems by looking at the complexity of the optics..