Roush How to tell if a Roush 427R is real or not?

I've been looking at a 07' Roush 427r Mustang locally and managed to get it down to a fair price...well I went to get an insurance quote on it before purchasing (assuming it would be expensive) and when I gave them the VIN it reported to them as being a Mustang GT Deluxe. It has the correct plates (from what I can gather) under the hood. From what I understand the 427R starts out as a GT Deluxe before Roush gets it and then resells it as a 427R. So is this correct or should I continue looking for another car?

Thanks!