I reckon they scanned it - super easy, as I doubt we'll be seeing the interior either.
If they had modeled under the sheets, it'd be possible to pull the model apart and look up its skirt, so to speak, so that would be a very bad move if the car absolutely must stay secret until Jan. 13th. I don't know why it matters either way, the final C7 will be in the next game if not in GT5, so modeling the car under the wrapping isn't doing any harm. The wrapping is mostly a testament to PD's artists' excellent texturing skills.
EDIT: It seems it does have an interior (that'll teach me to miss a day on the forum!), and there are already attempts to peel off the camo in photomode. Maybe it's part of the hype. Still, if the car underneath the camo is complete, then all they did was take a bit of extra time to add the camo, which is "required" for the early release - I think it balances out.
The "black mask" GT-R probably still counts as the first; as mentioned, the prototype was well known already, so there was no need to cover up the body shape (although there were a few tweaks). All that really changed from the prototype was the styling on the bumpers and light clusters. Plus, the specifications were closer to the release version, whereas the prototype was probably only ever a guess.
You can guarantee there'll be more of this sort of thing, expect cars whose "image" lines up with GT's nascent brand image to feature in future, and the same for other games.
