There were plenty of variances from the factory. You could take a piece from one car,and it could be off,if you put it in a different car. I have studied a bunch of original and concours-restored Chevelles and GTO with the red interior,to see how it would have possibly been done for Buick. As you know,most colored interiors are two-tone,and sometimes 3-tone. A lot of it depended on if it was metal,plastic,or vinyl. It would be easy to just make everything the exact same color,but it doesn’t look as sharp.