FP, yes, PlastX is fine on that surface or any other clear "plastic" with "plastic" being a very broad and general term. The problem can be finding an applicator that doesn't mar the surface. You can apply baby oil with a terry cloth towel and scratch the surface, and it sure ain't the baby oil doing the scratching!! It can sometimes be difficult to polish scratches out of some types of plastic and still achieve an optically clear finish. A soft foam wax applicator pad is going to be your best choice, using moderate pressure to start and lighter pressure as you go.

You have the wind restrictor from windrestrictor.com (King Penn Ind.) same as I do, don't you? Mine is getting scuffed on the surface that contacts the rear bulkhead due to very slight movement over time, but the main piece that actually blocks the wind is still fine. I have yet to play around with the lower half to see if I can pull out the scratches without inflicting any light marring caused by the applicator. It ought to work but it can be tricky.