I am pretty sure the boot carpets were all the same in AU series sedans based on spare wheel size, the only differences were based on colour, year model (some AU1's were different to AU2 & AU3), SWB/LWB and if it had factory LPG. So in essence your carpet should be the same if it has steel or alloy wheel.
What size alloy do you have as this will determine the wheel clamp, there are a few to choose from.
Alloy wheel (less 17" wheels) take AU 1382 C clamp.
17" alloy wheels like those on XR8 take NUTVE 1A381 A.
At a guess, I think you need the AU 1382 C clamp?
Similar to this..
https://www.ebay.com.au/itm/32415230...84.m1555.l2649