I have a 79 Malibu and do not know what this is for. Where the rear of the door meets the body below the striker on the body between the body and the door is a white piece of plastic. The car is gone for paint and the guy doing the work wonders what this is for and if he should just lose it and fill the hole before painting. I think it has to do with seat belts??? The car is a couple of hours away so I can't just go look at it or take a picture. Thanks for your help!!!