Brownell's gunsmithing supply (Montezuma Iowa) sells a rifle stock bedding product called "Acra-Glass Gel". It's a very high strength epoxy that is reinforced with finely chopped glass fibers. The stuff is as tough as woodpecker lips, and it can be carved and shaped with a Dremel tool or hand-held scrapers. They also sell a dye pack that would allow you to do a pretty close color match. I've used it on several occasions to either reinforce a damaged gun stock, or even mold some pretty intricately shaped small parts. With a little plaster of Paris and some ingenuity, you could cast an exact duplicate of the part with the stuff.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!