We (we meaning Eric) installed them on my painted fiberglass VFN hood. I wasn't there when he did it, but I don't recall him complaining too much. I expect it's no harder that drilling through any other painted surface. Tape it up and cut through paint so you don't scratch.
The key is finding a point to mount them. Mine are more inboard that Bob's, and also turned 90* to keep them in the channel across the front of the hood. Here is a picture (kinda dark, but you can see them) of my hood:
You can see the pins mounted in this picture also:
