That flat area sounds very odd, like a mod made for perhaps a front rest. I have an ex NZicon navy fultons and the stock is as per a stock no1 mk3, it does has the right half of the striker knob milled away though.
Joe Salter.com may still have the one he's been advertising, there's lots of pics at his site.
Very nice rifles to own, and collectible in that there's not many and they're accurate, they haven't hit their stride for value yet imho.