GOOD MORNING: Mayor Riordan and George Burns teamed for a photo op Thursday at Hillcrest in advance of a proclamation of George Burns Day and launching of the Burns & Allen Research Center at Cedars-Sinai Medical Center, where George and Gracie already have streets named in their honor and where Burns has already made hefty contribution$. While a CBSpec toasting Burns is off and he also canceled nitery dates in ’96 to follow his 100th birthday celebration at Caesars Vegas, the latter date’s on and sold out Jan. 17-21 (Jan. 20 is the birthday) … Caesars is shuttering its Century City offices (except for merchandising) and trimming the staff, which moves to Las Vegas, explaining that the local operation cost $25 million annually … I asked Jay Leno and David Letterman their respective feelings about the thesps set to play ‘em in HBO’s Ivan Reitman-directed “The Late Shift” based on Bill Carter’s book. Letterman is played by John Michael Higgins. David said, “I guess Buddy Ebsen wasn’t available.” Leno says Letterman’s comment about the TV show itself is his favorite: Letterman said, “It’s the biggest waste of film since my wedding photos.” Leno, commenting about Daniel Roebuck portraying him in the HBO’er, said several actors asked if he’d object to their playing him. His answer, “I’d never prevent any actor from getting a job.” Leno also reported the ratings win that Hugh Grant’s first TV appearance gave him has contributed to continuing success with the new audiences drawn by Grant staying tuned … Bob Barker (71) knocked down Adam Sandler (28). It was all for a fight scene in Universal’s “Happy Gilmore,” in which Barker makes his bigscreen debut after 39 years in TV! Barker, a karate expert, having been taught by both Chuck Norris (pre-acting days) and brother Aaron, says he took the job when he read the script and “learned I won the fight.” Barker now plans to ask Norris “Why don’t you put me in one of YOUR pictures — as a villain?” Barker resumes his 24th year in “The Price Is Right” after Labor Day.AS THE DAYS DWINDLE DOWN to Frank Sinatra’s 80th birthday, Dec. 12, the bombardment of books begins. “Sinatra! The Song Is You” is the latest arrival, with “The Frank Sinatra Reader” next. And Nancy Sinatra Jr. tells me she is busy in front of her word processor, delivering chapter by chapter of her “Frank Sinatra: An American Legend” to the General Publishing Group. “I’m trying to be a good reporter, researching, trying desperately to tell all sides of every story.” Her first book, “Frank Sinatra: My Father” was published in 1985. She’ll kick off the second book Oct. 14 on QVC with a package including a CD of Frank’s soundbites (receiving Oscars, etc.) and later the book’s followed by an even more deluxe group of five CDs from his RCA, Columbia, Capitol and Reprise albums. Nancy, who recently song-toured in South Dakota, will play Scandinavia in September and plans a large tour in ’96. Asked whether Frank will ever return to work, she noted, “He’s going to be 80 — isn’t it enough for him to stop shlepping around the world?”… And talking about writing/shipping: As author Ann Rule completes chapters of “Dead by Sunset” for Simon and Schuster, she also sends ‘em to producer Craig Anderson’s four-hour NBC mini scripter Wesley Bishop, who’s adapting it for the TV’er shooting on its real site, Portland, Ore. The book comes out in October, the TV’er in November. The true story of sociopathic chameleon Brad Cunningham stars Ken Olin, Lindsay Frost and Annette O’Toole and is directed by Karen Arthur. Anderson, nominated for nine Emmys for his Hallmark TVersion of “The Piano Lesson,” next produces “Snakes and Ladders” for CBS. HOWARD WEITZMAN IS ALREADY at work at MCA today, “excited and energized” with what he calls “my biggest trial.” Weitzman then works through the weekend with his best friend, Ron Meyer. Weitzman admitted the O.J. Simpson case “is one of the reasons I got out of that business”… A delay for Jackie Mason’s return to Broadway — because Los Angelenos love/hate him so much, his stand at the Canon is extended through Oct. 29. Where could Mason get better material than L.A. for his new “Politically Incorrect” show? … Eartha Kitt is a holdover at the Cinegrill where she, too, has broken every house record. She’ll do special 10 p.m. shows every night through Aug. 27 — and a midnight show on Saturday, Aug. 26. Can you believe Kitt’s celebrating her 50th year in showbiz? She started as a Katherine Dunham dancer in 1945 … MGM’s “Biodome” hit the roof in its first research screening at Agoura Hills. It stars Pauly Shore and Stephen Baldwin, produced by MPCA’s Brad Krevoy, Steve Stabler and Brad Jenkel (the team behind “Dumb and Dumber”), directed by Jason Bloom … Garry Marshall, wife Barbara and “ER” are among St. Joseph’s Hospital “Beautiful People” honorees Sunday at the Sheraton U … Arnold Lipsman, former press agent to thesps including Billy Crystal, has moved to Las Vegas where he’s director of public relations for the Mirage.