Nice piece of wood. real good chance that's a piece of claro walnut out of California. FWIW, There's not that much available for gunstocks anymore but you can still find a few guys offering it for centerfires and shotguns. I was in a warehouse out there 35 or 40 yrs ago that had over 300 stock blanks, almost all claro, some english, and brought home 5, two of which had curl as tight as a grade 5 maple stock. These were for centerfire custom rifles.
Steve