I've had bedliner on my fiberglass running boards on my 99 SuperDuty since early 2000. It still looks like new - no evidence of wear at all. The commercial bedliner guys can also put it down with a smooth finish as well as the rougher finish. I plan on getting bedliner put on the running boards on my '51, and probably will use it for undercoating on the fenders. Very likely will try getting the steering wheel sprayed with bedliner as well per FlatBlu4748's idea.
