I'd love to know too - where did the donor car come from? Was it a salvage? Someone's DD? 252k is up there in NSX land.
In a way I am thankful to them for taking a high-mileage NA1 to do this, instead of irreversibly modifying yet another pristine low-mileage example. These movies tend to have practically unlimited budgets as far as cars are concerned - I think they destroyed three or more R8s while filming the first Iron Man - so it's an act of mercy on their part that they didn't turn their unlimited budget towards pillaging a thinning herd.
In fact, you could say they even gave it a new lease on life - some collector or other millionaire will probably pay way too much for this car when the movie props are auctioned off. So they turned a 252k mile NA1 which probably would have sold for $20k into something a lot more valuable that will be well maintained as part of a private collection.