They're not even questionable, they're just outright wrong. By the time I got to the post it says "lane-change turn signal", but still states that drivers put their arm out the window before that, which is demonstrably untrue.

As for overhead cams, Delorean put them in GM cars, which was a first. More generally, there were cars utilizing overhead cams before Delorean was even born.

They got the recessed windshield wipers right, though.