Actually I don't know, but I don't think so. In any case it has not rusted through to the outside either underneath or on the sides of the van. The interior is all fiberglass and well sealed. There are two floor drains forward where water can flow out via duckbill valves. One could quite literally hose out the back of the van without any problem.Wow - that must be a rust bucket underneath all that insulation.
Currently, I plan to leave the fiberglass and insulation in place as if I remove it I would just have to replace it with some sort of insulation and interior sheathing. When I removed the refrigeration unit there appears to be about 3 inches of insulation in the ceiling I am guessing the same amount in the walls.
The big thing I worried about was that it might smell like rotten fish, but there is no order whatsoever.