I would think that there would have to be some structural reinforcing around the water heater opening. I've had my water heater out, and there was definitely a welded frame of square aluminum tubing that supported the water heater and reinforced the wall panel that holds the heater.
Of course, a '96 Windsor certainly has a lot of differences from my coach, but given the weight of a water heater and the water it contains, and how it is simply mounted by screws around the perimeter of the front frame, I just can't see it being held in place without some additional structure.
Adam and Sue, and a pack of little furballs
2007 Holiday Rambler Endeavor 40PDQ Limited Edition - Cummins ISL 400
2013 Ford F-150 FX4 toad - USGear Unified Tow Brake, Roadmaster Blackhawk II Tow bar, Blue Ox baseplate
Home base near Buffalo NY, often on the road to a dog show