Hello Auzzie, Possibly a type III or, without more detailed pics and not having my S&V book with me, it could be the 1 million commemorative model? It is still for sale?
It was couple years back and has disappeared off market somewhere.I never really found anything in S&V book that helped me but might not have looked in right area at the time. I got advice off Arts at time and they said not to touch too much risk as a sight unseen and cost of resto could easily outweigh any value. It was very beat up and had serious stock damage. What caught my attention at the time was fancy engraving and scalloping around ejection port was very different.