Since I have started looking for similar layouts as mine, I have only seen one other. It had a service body, and it was still in use.Thats a lot of work, but the truck looks to be in great shape and worth the effort. Not too many 3500HD crew cabs around.
I would be interested to see if your vin decodes to a 2DR cab. Some reading I've done suggest that the frames were extended for the crew cab after the trucks were built, and that possibly even the cabs were extended as well and thereby retained a VIN for a 2dr truck.
Would also be interested to know if your automatic balance dual tank system and fuel gauge still works?
Mine is an '01 with the 8.1L/4L80E, former Verizon bucket truck.
The vin does decode to 2 door.
Fuel system functions normally.