What’s the exact process to identify a real 66 Formula S Barracuda?

Michael Brisebois said
Amazing that we're still trying to decipher these things after 50 years.

I bought 66 mainly because it was unmolested.
273 2bbl
7-1/4" rear
factory 4 speed
13" wheels

I've actually never seen a factory 4 speed 66 with a console, but I had to add that...gotta have a place to put a coffee and plug in a cell phone

That is the way to do it. No secret, just need the fender tag and broadcast sheet. Does numbers matching really mean anything? Just need the right parts, like the factory did.