It works! The mcmaster part number is a workable solution. The ball is different so you have to modify the mountings to use it. It is zinc chromated so should be no problem with rust, the description says steel and I was thinking it was bare. The mounting on the door with the factory bracket is really not very strong. It is held on with two screws through the thin bottom aluminum trim on the door. I used a longer aluminum plate and riveted it to the bottom of the door so enough extended out from the width to attach the ball. The ball studs on the mcmaster parts are longer then needed, so cut or relieve.
There is another option, 10mm Quick Release Spring for Gas Strut RV Trailer Camper (KEF-10-110-QR), but I inquired and the lady said it works for both 6mm and 8mm, how I don't know, so enter at your own risk.
Drilling the balls off the OEM mounting brackets is easy, the metal is pretty soft.