It should be up in the window on the dash, which I think you already state, and then it's also on the inside of the door.
If they are having to do that much frame-work, I would think the truck should be totaled...? When my wreck happened in my first ram, they told me that the frame of the cab had messed up and it was going to cost a lot more to fix than the truck was worth...Are you sure you brought it to a shop that knows what they're doing? I could be misunderstanding here, or just not have a very good idea, but when I was reading what you described I just kind of shook my head in disbelief that they were considering basically taking your frame apart and bending it back into position...?
Be careful with this man. There are a lot of guys on here with much more experience and knowledge with insurance companies(they'll chime in eventually) that will make sure you get taken care of and not screwed over, but I figured I would help you out with another vin location