We use bra on ours. We take it off when in situe for more than a week or so. We have been full timing in our coach for a little over ten years. The bra has done a good job. Of all the places on the coach the only part that looks almost as good as new is the front end. I am a believer in bras if they are of good quality and they are removed when not travelling.
Our clear coat is starting to peel a bit across the top of the front (where the bra doesn;t cover). If it is just your clear coat looking faded on your give it a VERY LIGHT wet sanding with 600 to 800 grit and then re spray it with Spraymax 2K. It is a two part clear coat that mixes in the can before you spray it. You will need four coats. It will look brand new.