If it isn't to bad you can fill the holes with a mix of Gorilla Glue and Walnut dust. I mix it till it is thick but first put a smidgen of the glue in the hole then push the paste I made in and let dry. It will be hard as a rock by morning and then you can sand to shape.
Now if it needs wood replacement you can razor a square carefully then chisel it out. Now you use a belt sander if possible to taper all four sides of a chunk of Walnut to size of repair and set it in the spot. You sand a bit more and check repeating until it is a snug fit. Glue it in place with Gorilla Glue and clamp over night. It isn't a cake walk unless you have worked with wood allot. To me it is very simple now from years of practice. Worst thing is if you slip and make the repair larger or cut yourself so be careful. The stock's below had to be done without removing the original finish. Rick B
1954 Winchester 30-30 which had a name plate removed and a worn out cut-out form years of it not bing in there.
1941 Johson rifle
