In talking with Eric - there are cases when guns still coming out might have seemingly ''odd'' parts.
By that I mean .... they had IIRC some 70 or so frames from earlier, which had been rejected for finish - that in itself for minor flaws ... hardly a major factor other than aesthetics.
These frames have since been up to CT I believe, and been refinished to current (perfect) spec' - and so those frames will be coming out on guns now or soon, showing some of the earlier serial numbers. Which might on the face of it seem unusual if the number was viewed in a purely sequential sense.
Furthermore, I believe also, there are a few ''Farmingdale" slides still coming out - perfectly legit as they were made at Farmingdale! Could be here, a few folks will seem to be getting a much earlier gun - when in fact they are still newly assembled and tested. There will be therefore I guess a few more guns appearing here and there with slightly more ''collectible'' features.
Eventually, guns will be coming out almost sequential - this I reckon is probably the last phase of more widely spread S/N's.
So - this is as I understand it currently - and hopefully I have gotten my facts straight.