This is that gen dial I was watching ob ebay previously before going gen, I figured, that I will be needing the correct caseback which is another needle in the haystack;
https://www.ebay.com/itm/Genuine-Omega-Used-Seamaster-300M-Blue-Dial-2537-80-00-40th-Anniversary-Model-/223992123517?epid=648197645&hash=item3426f8907d%3Ag%3Avx4AAOSwuJped5Ia&nma=true&si=OrgHO9IXAym2ZJ1DQwnheJviTh8%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557
Is this the franken watch you are reffering to that was sold on ebay?
https://www.ebay.com/itm/Genuine-Omega-Used-Seamaster-Blue-Dial-40th-Anniversary-Swiss-ETA-2824-/124166431217?hash=item1ce8e561f1%3Ag%3AP7MAAOSwCKlepNHw&nma=true&si=OrgHO9IXAym2ZJ1DQwnheJviTh8%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557
I do have an A21J version of the 40th anniversary but is already modded with a gen 2531.80 and is now on my brother's wrist - will be moving the watch to new case soon
here it is;
OG setup
with a poorly bleach bezel mod (LOL) and a gen 2531.80 tritium dial from Mr Pap (missing his Omega Gen parts sale nowadays)
and with the new bezel from my chrono diver (bent the OG bezel upon removal) gosh its thicker and is really not a good fit but its ok
The whole album;
https://imgur.com/a/0gSpi9F
Lastly,my newly acquired gen 2221.80