"Is there any evidence that even one person was convinced to buy a Dodge from one of those commercials?"
Not to the exacting scientific standards of this forum of forums I fear!
Together with the finish influencing sound-theory, the Loch Ness monster, the true origins of TV yellow, Gwyneth's extra-marital affairs with older men, "who knew what ahead of Pearl Harbor", the (not!) moon landing, the lingerie(ng) question whether George was really fast asleep when they dressed him in women's clothes, "9/11 was the CIA and Mossad" and the Immaculate Conception it has to go into our "uncorroborated myths and allegations" bin.
The Last Bass Outpost - where facts and nuthin' but(t) count ...