Richard, thanks for your theory, I've never heard of this kind of arrangement with any of the equipment honestly when it comes to KMZ stuff... especially with something so common and mass produced as Helios lenses.. with KMZ really in Soviet era it seems like you get fairly consistent high quality lenses, optics were never a problem. I've heard of some prototype cameras given as presents to some officials or leading engineers on the projects and then there's the whole "Syezd" stamped equipment that WAS given to officials as presents.. actually denoting quality of an item with serial# goes against the Soviet principles of mass production

. Extremely high quality items may have been set aside manually, and one way I think it was done with some cameras at least - they would get the CCCP Quality stamp (which I am not sure what the requirements were to get that, some kind of approval by someone I would assume).
Zoom, any ideas - any significance of no year prefix here? I have a few Helios-44(-2)'s that have the same kind of numbering system and some have year prefix.. I wonder why..