You might check a product out called Shine On. Here's a link.
Shine On Online
The guy has a youtube video on the web page where he demonstrates the product and it looks like it does a pretty good job. No idea how well it does long term. I have never used it and I don't have any affiliation with this company. If I ever have fading or oxidation issues on my rig I would be inlcined to try this before I start buffing on it. I'm in the car wash business so I have experience buffing, just not on fiberglass/gelcoat.