Said the watch is actually made from a 1966 Mustang with VIN??
I've never seen a 66 Mustang VIN like in this ebay listing ::)
Possibly 6F07C185502 ??
https://www.ebay.com/itm/REC-Watch-P51-02-Made-from-a-Vintage-1966-Mustang-Automatic-26-Jewels-Mint/223427235545?hash=item34054d0ed9:g:~x0AAOSwAnxcfzdw
Now this one seems legit on the VIN: Metuchen built "A" engine code....
https://boston.craigslist.org/nos/jwl/d/lynn-rec-51-mustang-watch/6827710400.html
It looks like all their promo material uses the same non-serial number, 6F87C85151, with production pieces receiving real serial numbers.