This year’s Kennedy Center honors have been announced: Dustin Hoffman, David Letterman, blues musician Buddy Guy, dancer Natalia Makarova and the rock band Led Zeppelin.  Led Zeppelin is being honored as a band, but keyboardist-bassist John Paul Jones, guitarist Jimmy Page and singer Robert Plant each will receive the Kennedy Center Honors. Drummer John Bonham died in 1980.   The gala is scheduled for Dec. 4 at the Kennedy Center in Washington D.C., and will be broadcast on Dec. 26 on CBS.