Not true
You can even download the song from the Um Bongo web site.
(OwlofDoom is new around here, Sat 7 Apr 2007, 11:46, archived)

hooray for the um bongo song!

( Wortal Mombat - Whistling Dixie, Sat 7 Apr 2007, 12:27, archived)

Um Bongo
I spent a couple of days in Congo last November trying to buy a carton out there. :^( They didn't know what it was despite me singing the song to several people...
(travellingsteve, Sat 7 Apr 2007, 22:47, archived)