When I started the Cinelli Registry back in 2002 it was pretty obvious even from the first dozen or so serial numbers I collected that there was no "pattern" that I could discern, related to time, sequence, calendar, or anything else.

one person whose judgement I respect has conjectured that there may have been some obfuscation going on to confuse the tax collectors. That's certainly a possibility.

I would simply suggest that there may have been other factors at work. Frames farmed out to different builders, or hanging on the wall unsold.

my personal opinion is that this is not a problem worth worrying about anymore. A true case of "it is what it is".

/markp.