Sometime you have to man up when you make a mistake and since the transitional is my favorite reference I could not let the incorrect information sit out here.
I went back to post a picture of the movement and noticed I wrote down the wrong number when I looked at Al's service pictures 3 years ago. Let the thread stand corrected that my 145.022-68 S/N# is 26558691 which brings it more in line with the documented transitional serial numbers.
I know I am pulling up an old thread, but I couldn't help it. It is weird to me that a 321 movement with a lower serial number has a production date almost 4 months AFTER an 861 movement with a higher serial number. Maybe these were sitting on a shelf somewhere in the factory? Maybe someone came by and said "we have to ship these outta' here".
So there (apparently) isn't overlap in serial numbers. However there is (quite a bit of) overlap in production dates. I would say that lends credence to oddboy's postulation that 861 serial numbers started at 26,xxx,000. I bet someone had to count the remaining 321 movements; they then defined that 861 numbers start at the next even 1000.
It is also really cool that the 321 was manufactured only 2 weeks before the moon launch.