Bing Crosby singing White Christmas
That was the #1 song in 1942. (Other top-selling bands/artists include such rocking names as Glen Miller, Woody Herman, and Jimmy Dorsey along with their respective orchestras.)
I did find the book I was looking for-- The Encyclopedia of American History (1965) which I've written about, it's a great book. It put me on the trail of White Christmas which I've written about. Wikipedia confirmed the song's status for '42.
So to recap... .
ZZ Top : undergraduates in 2014
Bing Crosby : undergraduates in 1978
I don't know what to say other than go see ZZ Top in concert at Mississippi State University October 30th.