Yeah I'm pretty sure those would be the bumpers you need. They attache on the hatch lid deck and seat on the area you shown on the picture. BTE, I would sand, prime and paint those areas right away so as to avoid further deterioration. When you get the bumper parts and install them, I would also get a few of the clear adhesive little "thingies" ( like you put under a glass table over wood) and seat them right where the hatch bumpers sit on that area when closed. It will help protect, limit the need for precise adjustment to the bumpers and also stop any rattle noise from play in the hatch while driving. I'm pretty sure that's why the paint is worn there and it's rusty. The previous ownwer/s didn't have them seated or adjusted properly and it shook rattled and rolled while driving, rubbing off the paint.

Enjoy the car, if you ever get it back from your son.