Ahh, the PDP (Purple Door Panel) problem.
A bunch of 95s, but also some 94s and 96s, suffered from this. Namely, "something" GM used in the process of making the panels caused the panels to turn purple over time. When in contrast to the window control switches (which DIDN'T change color), well, the door panel came out to look "off" in comparison.
It was such a pervasive problem that more than a few SS owners back in that timeframe got GM to replace the panels for free under warranty! In fact, I wouldn't be shocked if some of those purple panels (which, other than the color issue, should be fine physically assuming they were stored properly) end up making it back into the used parts market
To "fix" it, you'd be looking at re-dyeing the panel. Something like SEM could work well here. Would also make a great base if you wanted to try something "custom".