Perhaps you are thinking of laminated stocks. They are made from laminated veneers and can be produced in a variety of styles and colors. They are quite popular, especially when people want to get an after-market stock of a different shape. Companies like Boyds Gunstocks, for example make laminated stocks in different styles for a wide range of rifles. Weihrauch offers some of its HW97's and HW77's in laminated stocks.
Son-in-Law is into making knives and shared this Youtube video with me for ideas on grips.Called Micarta, the process uses fabric / canvas and epoxy / fibreglass resins compressed together.Thought it might be an option along the lines of what you're thinking.
I think the OP is referring to the Walther Terrus. I don't own one but I read a review that said the stock was made of wood fiber.