Well I just found something on ebrsopmods. com I don't know how reliable the source is but it seems legit...
Commercial Production Hand Guards - Between 1978 and 1994, Springfield Armory, Inc. sold heavy walnut match, fancy burley walnut, extra fancy AAA grade walnut and laminated walnut/maple hand guards for the M1A. It has installed commercial reproduction plastic hand guards on M1A rifles from the mid-1990s onward due to the scarcity of new USGI hand guards. Early plastic hand guards were shiny but later copies had a dull finish. Chinese M14 hand guards appear to be manufactured by injection molding. They are marbled brown on top and silver on the bottom. The bottom side is marked DT25. Reinhart Fajen, Inc. offered matching wooden hand guards when it was producing M14 stocks. Boyd’s' did sell matching hand guards (walnut, nutmeg laminate and pepper laminate) for its wood stocks until production ended in October 2007 and then again beginning January 2010. Wenig Custom Gunstocks, Inc. offers walnut and laminated birch hand guards for its M1A Scope Stock. Commercial wood hand guards are noticeably thicker than the USGI wood hand guards. Fulton Armory offers a more rugged solid glass-reinforced polymer brown color hand guard, as compared to even the USGI solid fiberglass hand guard. The Fulton Armory hand guard may be ordered with an optional black color textured epoxy coating. Fulton Armory glass-reinforced polymer and Springfield Armory, Inc. plastic hand guards are not silver color on the bottom side."