I can assure it is a GT42 with a modified rear housing to a T51R 1.05 a/r.
I purchased it from a distributor i have been dealing with for years. The company is one of, if not THE bigest turbo distrubutor in Australia running for over 20 years now.
As you would know there are quite a few different compressor cover styles available and all have different pros/cons... i can assure you that the blades are still the same.
Regards,
Riste.