1968 GTS emblems

So when were they red and when were they black.

Could you get red or black on any body color ? Or did only certain body colors call for either/ or??

Also when equipped with a 383, did the 383 emblem on the fender always match whatever color the gts emblem right above was?
Mine were original to the car, and both emblems black background. Car is GG1 Dark Green