Of course I wasn't there and probably neither was anyone else here that was on the assmebly line back then.
I recall a thread that they said they had a painter back then when they built the cars in a walkway below the car. As they came into the area, he sprayed the blackout on the front. I never recall seeing blackout treatment on the baxkside before. I stripped mine this summer and it didn't have it there.
There would be no reason logically I would think for them to treat a T/A or AAR any differently than any other E Body on the assmbly line.