Theses are the BA Falcon rear discs. I think these are what's installed standard on the GT Falcon.
The discs measure 300mm compared to 285 for the AU2 but that seems to be about the only difference.
I'm contemplating keeping the AU2 discs now and putting them in the cupboard. I'm thinking it might be good to have some brakes I could throw on if I get a pair of 15" rear rims with drag tyres. I'm not sure a 15" rim will fit over these.
Cheers