I have ONLY seen this from the box, never one on one. Looks like at one time these vans had open windows in the back passenger area. I wonder if this one will have that. I would like to build a factory stock open window van. http://round2models.com/models/amt/chevy-rescue-van
The side panels have been permanently and irreversibly "installed", so this body can never go back to the original version with upper separate inserts without a major reworking of the body shell. I'm guessing Round2 looked into that possibility, but considering the most recent "Dirty Donny" version is what currently exists, and the Rescue version's box art depicts a panel van, going back to the original body shell isn't something I'd expect to ever see happen.
Here's the original Rescue vers