67 GTX tail lamp bezel colors?

[gtxno1]

Hi everyone why did they make 2 different colors on the tail lamp bezels on a 67 GTX one is argent and the other is red on the inside was this a trim level thing or based on the exterior color of the car

 

[67 GTX]

I believe they're all supposed to have the red streak running from top to bottom, but on older cars it fades away to the point you have to look close to see it.

I don't believe that fell under any trim designations.