From the research I did before installing my roof vent, it seems the headliner is installed at the factory before the windshield is installed. I am not sure if you can get it out of the car without bending it and without removing the windshield.

When we installed the vent, we just moved it to the back of the car, resting it on the rear deck and the front seats (reclined) to keep it supported. I don't think we could have gotten it out, it looked to be to wide for the door opening.