My whole dash board is missing!

If you have the build plate, title and the dash vin from the parts car and its the same year and model, just swap them to the other car. If your car is not a special model like a 340 or GT or something of higher stature no one will be concerned. Most people dont know there are a few places the vin is stamped in the sheet metal.

Another alternative would be to have someone duplicate your dash vin tag. I think Galen Govier does this - but it is not cheap from what I recall.

If it were me, I'd look into option 2 - if its possible to duplicate it, then have the body shop pay for it. If they wont pay for it then do option one.