FINAL CHAPTER Readers and mourners eager to buy books on John F. Kennedy Jr. won’t have long to wait. Publishers are rushing out with updated titles. At this point, no authors have submitted proposals for serious new biographies of Kennedy, though Sally Richardson, senior vice president of St. Martin’s, says she’s rejected eight proposals for quickie books in the last week. ”He’s above the kind of revelations investigative biographers traffic in,” says Random House senior vice president Stuart Applebaum. Adds Simon & Schuster VP and publisher David Rosenthal, ”There’s also a sense that there’s been so much [news] saturation, what’s a book going to contribute?” Still, at least two authors are mulling over the possibility: C. David Heymann, author of a recent Robert Kennedy biography, admits he’s written a proposal for a JFK Jr. book but hasn’t made up his mind whether to do it: ”Jackie and Robert were public figures, whereas John Jr. never was, so the question is whether the life really lends itself,” he says. And Jerry Oppenheimer, who postponed his JFK Jr. biography to write about the Clintons, says he hasn’t decided if he’ll return to the project. In the meantime, Carol Publishing is updating Stephen Spignesi’s The J.F.K. Jr. Scrapbook, retitling it J.F.K. Jr., and bringing out 75,000 copies. Signet will revise its 1994 Prince Charming, by Wendy Leigh, publishing 100,000 copies, and Kensington is rushing to press with The Kennedys: The Third Generation, a new paperback previously scheduled for the fall. St. Martin’s is sticking to an October publication for Jay Mulvaney’s Kennedy Weddings. The tragedy has also sparked interest in What’s Heaven?, a children’s book that Maria Shriver wrote after the death of her grandmother Rose Kennedy. St. Martin’s has just gone back to press for an additional 50,000 copies.