Look under the Industry News Forum-- there is a sticky with contact info for Steyr in Georgia. You might see if they can order it for you. I have also heard that it is a stiffer stock. Mine is OK on cold days, but gets rather pliable on a good hot Alabama afternoon hunt.
Good to see a rifle question-- in my opinion, Steyr rifles are superb, I just wish they had done the stock improvement before I bought mine. Does yours have the older, hard to lift bolt? Mine did, and a retrofit made follow-up shots a breeze