I always wondered how much production info could be gleaned from Seiko's serial numbering system.
If they absolutely maxed out the production for each model and for each month within the confines of the serial numbering system, then I suspect that your production estimates would be accurate. But I doubt that is what happened. I suspect that Seiko adjusted production of each model from month to month based on sales of that model. Maybe in some months they made 9,999 casebacks (which is the only part of the watch that is serial numbered). But it is possible that other months they only made half or 1/4 of that. In other words, perhaps production broke down like this...
May, 1979--9,999 pieces
June, 1979---6,209 pieces
July, 1979---4,802 pieces
August, 1979---3,432 pieces
Sept, 1979---5,566 pieces
It is just hard to tell how many of these were actually made, but I do know from talking to people who purchased watches in this era that these divers were VERY popular when new. I suspect that they were made by the tens of thousands every year from '77-'88. Seiko can't (or won't) give us any info on the subject.
They must have been made in HUGE numbers because even after 30+ years of attrition they are still a very common watch. That can't be said for the Submariner, though it certainly is not rare as a model. There are lots of Subs around because they have been made for 40+ years, but I think in terms of yearly production they would be way behind the 6309. The 6309 was made in much greater numbers annually...but for a much shorter period of time. JMHO. ---A
