Tag Heuer 510 500/12

Hi guys, my first post on the “THF”..
So this absolute stunner came into my life yesterday (from a regular guy I buy watches from at my local antiques market).. I bid strong money for it, so wasn’t cheap, but the overall condition is as if it came out of a time capsule..Dial and hands are 100% incredible, the bracelet looks hardly worn, clasp snaps shut as if it was like new, case back still has “sunburst” finish. The Lemania 5112 is keeping excellent time..
My research has unearthed very little about this particular model..I’m thinking it was manufactured at the very beginning of the Tag collaboration with Heuer.. 1985/86?
Also very hard to put a value on it..
Please guys chime in..

Congrats and welcome to the forum!

Beautiful watch! These were actually originally launched in '82/'83 as Heuer and then carried over after TAG's acquisition in 1985. In fact, it was the only Lemania based Heuer to live on as a TAG Heuer.

You can read more about your watch here: https://www.calibre11.com/heuer-510-500/

Congratulations indeed - a very nice watch.
I'd put it a little later in the Heuer / TH transition timeline, right in the middle of the infamous parts bin days - so roughly '86-87.
The "original" 510.500 indeed started in the early '80s with the Lemania 5100 inside, then the 510.500/12 with its slower beating 5012 was the replacement. Like your own, most of them mixed Heuer- and TH-branded elements, with the crown almost invariably with the Heuer-only name and the dial and caseback with TH - whereas the bracelet could be either.
The fun part about this is that TH is rumoured to have had to basically re-build the 24 counter which the L5012 lacked out of the box, after having used up their L5100s on models such as the Silverstone which did not need it.
Some people may have their own preferences on what watch version looks best among its various incarnations: the early day-date Heuer 510.500, the later date-only, or the TH final version. On the TH version I really love the "fat" indices on the dial, but I prefer the thin-pointed time hands and the arrow-shaped minute chrono hand of the Heuer versions. The place where the TH version wins hands down is the bracelet with its half-moon links, both more substantial and more comfortable than the flimsy flat-links Heuer version.
Value-wise: a very hard call. If you look at the ones up for sale, you'll see crazy quotations - but I strongly doubt any of them has sold at those sky-high prices. I think a fair value for one in the same conditions as yours - accounting that it may well need a service which is costly on all L5100s - is about 2000 USD / EUR.
Cheers,
Fabrizio