I did the same thing. I bought the gun with the walnut stock, finished it, then decided it looked too nice to risk putting a dent in it.maddon said:
So I bought a well-used surplus fiberglass stock from Cheaper Than Dirt a couple of years ago, painted it OD green, and used that. I liked it, but it had been pretty battered before I bought it, so I bought an unissued fiberglass stock from Fred's. Using the experience I'd gained from the banged-up stock, I did a really professional paint job on it, and filled in the selector switch stock with a Sparrowhawk dummy kit.
Now I have three stocks for the M1A, one for special occasions, one for normal range use and another for SHTF. Nothing like variety.