CAMP COUGAR: John Mellencamp returns to the...

CAMP COUGAR: John Mellencamp returns to the concert stage Monday night when he’s scheduled to perform a surprise show at New York’s Carnegie Hall. The occasion? Mellencamp’s new album, “Whenever We Wanted,” which he will play at Carnegie from start to finish. The record features 10 new songs, including “Love and Happiness,” “I Ain’t Ever Satisfied” and “Crazy Ones.” Even though Mercury has a crowded fall release schedule, Mellencamp’s new album ships Sept. 30--and for an intriguing reason. It’s the last day albums are eligible for the 1991 Grammy Awards, which has become an important sales vehicle for publicizing the success of mature rock artists (witness the huge sales boost Bonnie Raitt got after her Grammy sweep last year). . . . And our favorite case of Mistaken Rock Identity happened at Buddy Guy’s club appearance at the Roxy last week. After calling Eric Clapton up to jam, Guy also asked his sometime drummer, Richie Hayward, to join him on stage. But guess who bounded up? Bon Jovi guitarist Richie Sambora , a longtime Guy fan who’d been on hand, hoping to play as well. Somewhat startled, Guy whispered to Clapton, “Who is this guy?” Guy graciously let Sambora share the spotlight--and visited with him and Clapton after the show.