Fiberglass Taillight Filler Plates???

Allright, nobody makes filler plates for the taillights on my car. My car is a dodge avenger and the taillights have a big compound curve to them. So it would be very difficult to make them with the tools i have. I was thinking of making a mold of my taillights and then lay a lot of layers of fiberglass in the mold. Whats ur opinions on this???????