Wouldn't you know it, the mercedes door handles from 1985 used slotted holes[1]. As much as you like them, Mercedes cannot transcend the technical abilities of the time.
I guess my comment was more about the general build quality of US cars from the 70s. I have worked on some and it seemed they were just thrown together without any thought or care.
No argument there. They were definitely not going after the "luxury" market segment (and still don't)