The answer is that nobody knows..
The serial range that Reds fall into is a range used for the entire Rolex line.. Out of that range, there is no way to know how many of what model were allotted which numbers..
For example, if they ran for 8 years, and the Red Sub accounted for 4% (a fictitious number) of the total 300,000 watches produced during those years, then they made 12,000 each year, worldwide.. times 8 years = 96,000
That's my guess.
