In a 1995 interview Bob Denver explained that he went to the higher ups at CBS and said that if they wouldn’t change the theme to name The Professor and Mary Anne he’d give up his spot. He felt they deserved the same billing as, well, the rest. Dawn Wells didn’t know until that moment.
The revelation comes in around 3:30 but the whole interview is really nice.
I watched “It Happened on 5th Avenue” last week, and it has the young Skipper in there. I saw the credits first and thought it might be his father, Alan Hale, but it was Jr.