Nothing major was done, to any of the cars that they(Honda of America) have. If any thing big needs to be done they have sub systems of the cars on stands( engine, trans, p/s systems and so on). The cars themselves are used for stuff like wiring and troubleshooting using scan tools(HDS) to comunicate with the car.
Oh and the cars are taken pretty good care of. They stay inside year round and every week they get detailed. The only major thing that I saw that would develop on a training car was it acquired quite a few door dings.
That car while I was there looked pretty good except it was missing the front lip spoiler. I kinda played with it for a while.....just to show the other techs that are not familier with the NSX, how to open the hood, hatch, and trunk.
I'm sure it will be a really nice car and is worth what the seller was asking, just a questionable past.
Good luck.