I know this is really old post but I thought an update may help someone. As of NOW September 2023. Paul's Chrome in Pennsylvania (800) 245-8679 no longer plates fiberglass. Some of the products they used to make the conductive base changed and they no longer get reliable plating.
I found Metal Fusion in Texas (940) 276-0034 that does. To plate a 1969 Ford Mustang rear fiberglass bumper is $2200. It was a bit of sticker shock. For comparison Paul's in Pennsylvania currently charges around $1000 for plating the metal bumper. Both shops stated show car quality plating.
Hopefully this update is helpful.
Charles in Pensacola
69 Mach 1 Mustang 428 CJ Shaker hood R code
Link to my build on Utube