Formula S plastic grilles are moulded in black plastic and the silver barracuda grilles are moulded in a gray plastic and then painted silver.
If your gonna try doing some plastic repairs,which I have been doing for years.I will suggest a product made by Devcon thats called plastic weld and I can find it around here at the local hardware stores.
I am redoing 5 69 grilles right now,so if you have any ???? ask away.
Doug