Why are you shopping parts? Insurance will pay to repair your unit. Have it taken to a body shop. If the repairs cost less than the deductible, you will pay in full. If the repair costs exceed the deductible, you will pay the deductible. If you put the tailgate thru the door, there is likely additional damage to the area where the hinges connect to the trailer body. Plus, isn't the door painted to match the unit? Your insurance should cover all those additional damages and costs of installation and repair.