Bob, which Walther match rifles ? If you mean LG55 springer then yes,trigger guard. If you mean ssp LG90, LGM-1 and LGM-2 and 210 then apart from the actual trigger blades there is no 'plastic' that I have ever seen 'in' them.
The LGR Walthers first ground breaking ssp only had the same plastic trigger guard as the 55 and a plastic cocking handle.