Well so far, everyone who has responded has said theirs was black underneath, with your possible exception of dark gray.
My 79's and an 81 have black, so I thought the TATA would the same, and it appears they are. I wanted to see if the factory did anything different with them underneath, like spraying it all body color or a different primer color.
There was the TA specialties restored TATA, where they painted the bottom gray, which I wondered about. And another guy mentioned he has an 81 SE that he said had gray under his low mile original car. And it's not a dark gray. He put up some pics. It looks more like a lighter to medium gray. So, I was wondering if there are any more out there with gray.
Thanks for the pic Bentwheelbob. But we know 78 and older are red oxide, so no mystery there
. This topic is really about TATA's and 79-81's, and whether anyone has seen a different primer color than black on them. Thanks!