Based upon my personal experience working on powder coated surfaces, powder coated surface don't lend themselves well to being polished or abraded in any way with the end result looking original or better.
Powder coatings don't react like a normal automotive paint.
About all you can do is wash or wipe clean and apply a coat of wax and this might add some shine.
If your gonna try polishing I'd recommend working on a small test spot first. Some Meguiars M86 So1o Cut & Polish Cream and M105 Ultra Cut Compound would be my first step since they lack solvents that can sometimes soften a painted/coated surface.
Someone else may chime in with a different experience and some hope...