Close, but I don't think they use fiberglass. There is a mat or cloth type material you add a resin to, the wrap on my grip and cheekrest is a piece of Tshirt with resin to make it hard. I plan on making a body for the chassis out of real fiberglass cloth, just need to make a mold. Currently, it is only a fiberglass resin coating, it has helped tremendously for keeping paint from chipping or wearing off.
You can even use hockey tape as a material for the resin, simply wrap what you want in the tape, then add the resin.