Changing a truck cab

I would remove the doors, just to make it lighter, they are real heavy and most need the hinges rebuilt any ways.
Plus it will make it easy to do any other repairs if necessary.
Before final torque the cab bolts to the frame, I would re-install the doors with the hinges rebuilt, and in perfect align with the cab.
When you final bolt the cab down make sure both doors are closed to not tweak the cab.