Grant,
The particular stocks on those rifles were finished by Darryl Stevens at Fernvale, between Gatton and Ipswich in QLD, he's near the Wivenhoe Dam.

The 450 Ackley wears a stock from Richards Microfit, called a #102 Classic and the 500 is a Boyds JRS Classic, which they no longer make for an M17.
Boyds do make a RIA Sportsman for the M17 in either Nutmeg or Pepper laminate, they are about $90-00 USD, unfinished.
I've got a "spare" one for the 500 in the cupboard, just in case it decides to split one day. In 415 rounds fired so far (and Yes, I'm that anal that I record rounds fired in all my rifles!) it hasn't shown any signs of wanting to do that.

Regards,
David