Fibreglass is a nightmare. It expands and contracts with the weather, which isn't good for the paint. It also fades quite differently than plastic and metal, but not really enough for an untrained eye to notice. Hi-ryder is right also about the pinholes and ripples, fibreglass is notorious for it. If you put any bog on it anywhere to fix ripples or dints then I can guarantee that within a year shrinkage and/or cracking would have occurred due to the constant expanding and contracting of the fibreglass itself.
I'd scour eBay, gumtree, trading post, wreckers, for a second hand one or an aftermarket one that isn't fibreglass. You get what you pay for unfortunately. Although, there'd be less work in a second hand bonnet with dints as opposed to what you've got. Unless of course the "dints" are a result of a hail storm, lol.