Dozens of advertisements urged on the Mets en route to their championship in the 1969 World Series program, but only one looked like a notice placed by a proud parent in the Playbill for a high school production of Bye Bye Birdie (which, come to think of it, was the unofficial theme of that Fall Classic). I was given the ’69 program a dozen or so years after the fact and have always been intrigued by the quarter-page ad Marvin took out. Was he real? Was he a superfan without portfolio but a little cash to burn? Was he a fictional character? Was Marvin Buchsbaum, Jr. really invented to sell Right Guard? I’ve never known. It’s never mattered. It’s just nice to see such unqualified support.