door handle/mirror reinforcement plates

Assuming the plates are a good fit to the shape of the door.

I would assume that the urathane is to prevent moisture buildup between the plate and the door.

Why a difference between mirror and door, who knows.


Unless the instructions say 1/8 bead, I would think a light skim coat across the surface of the plates would do it.


Now the real question.

For 50 + years the handles and mirrors have worked fine. Why the need to add the plates.

The parts you don't add, don't cause you no trouble!