Probably not.
I believe that most aftermarket body panels are made using old dies purchased from the OME.
FRP would use molds. The molds would, I think have to be made from scratch which I think would drastically increase the price.
I think almost all non OEM produced aftermarket body panels are made in China or Taiwan with tooling they have produced themselves.
They scan the part, digitize, and build tooling.
They even produce all the sheet metal to build a vintage Camaros, Mustangs, etc.
http://www.dynacornbodies.com/manufacturing.php
Maybe. I'm more concerned about the precise composition though, especially if they had any special sauce for longevity or wear ( better than modern, that is).
Depending on what kind of tech used a mold is needed for every N parts, and molds can be made from a master with great staying power for long long runs. Play your cards right and you ma I imagine I'd rev the dimensions starting with a trip to the salvage yard and then refine from the original article using a probe attached to a CNC router. I'd use back-of-the-envelope or FEA to determine if anything special is needed for the attachment points and edges. Actually flat-ish stuff with minimal holes may work better with a simpler technique, where you make the starting mold from the original article.