Fancy grain walnut wood, may have had some finish added, face of stock altered for extreme drop, original Winchester marked black butt plate, fancy wood field grades are SCARCE.  Excellent.

W-26637 - Winchester Model 42, Pre-1964 Field Grade Stock

W-26624-F - Winchester Model 42, Pre-1964 Field Forearm Only

15 groove flat bottom variation, appears unused.     

Winchester Original Model 42 Stocks and Forearm