The research is still in process, but for those interested I have posted an initial serial number project for the Heuer 3646 (however, I'm focused only on the 1st execution dial and 2nd execution hands, with either the thicker pointed lume in the hands, or thinner rectangular lume hands, for the present). This includes a price trends chart as well.
https://alphahands.com/vintage-watch-research/heuer-3646/
More images will (hopefully) be added shortly.
If any I have missed, please let me know. Thanks all