Whatever you call it, for range or DZ operations, we call it the MEDEVAC. The dude with the biggest Suburban, or the eighteen pack with no seats gets called the CASEVAC.

This article confirms that the shelters are new build.

https://www.army-technology.com/news/am-general-m997a3-ambulances/

Thanks guys, keep your comments coming.
Still waiting on the photos from my son.
Matt, I'm feeling your pain on finding a kit. I got outbid on one on ebay last week. I didn't how rare they've gotten. I've only found one recently out of Ontario but its out of my price range. Nothing else on this side of the oceans. I would even settle for the Revell 1/72 twin kit 03147 with the TOW launcher HMMWV and the ambulance. But its just as scarce.
Will keep looking.
Thanks Guys!