I agree with LFW that the TR6 and TR4 interiors match as to the Bright Red interior. This is not say that there isn't a matador red interior also. I have a TR4 that I switched over to the bright red interior. I was able to use a bright red interior for a TR4, bright red seat covers for the early TR6 seats that I am using and a bright red rear piece from a TR4A because I have a hard top ( surrey top) car. All of these components from each of the three models all match perfectly.
But your question is still out there about what was standard on the TR4A. I will then submit to you that they would likely not be producing a bright red interior for all three models if it wasn't original. But that is a guess.
By the way in case you haven't checked the TRA Judging and Restoration Standards, they say the interiors of the TR4 and 4A came in black, red and blue. There is no description of the red. But then there is no description that there was more than one red either.
Charley Fitch
