The lunchtime crowd at Ago — the new Melrose Avenue restaurant at the site of the former Cicada — got to watch a Wednesday lunchtime broil between “Natural Born Killers” original screenwriter Quentin Tarantino and one of the film’s producers, Don Murphy.Tarantino had been dining with Miramax co-chairman Harvey Weinstein when he got up to confront Murphy, who was waiting to be seated. A bystander reported that the “Pulp Fiction” director “got medieval” on his opponent, scoring a volley of uncontested facial blows as Murphy tried to cover himself before the scrap was broken up. The L.A. County Sheriff’s Dept. was called to the scene, but a deputy said no charges were filed and the “parties settled the matter between themselves.” Tarantino confirmed the incident through his spokeswoman, who said it was the residual effect of some bad blood between the two and Tarantino’s feeling that Murphy had been badmouthing him around town. “I really think I slapped some respect into the guy,” Tarantino said. “We shook hands and agreed not to badmouth each other anymore.” While Tarantino wasn’t specific about what prompted the brawl, there were few kind words about him in the book “Killer Instinct,” the dissection of “Natural Born Killers” written by Murphy’s producing partner Jane Hamsher, which was just published by Broadway Books. Among other things, the book characterizes Tarantino as having a “less-than-spectacular acting career,” and, after noting he’d bought a $3.4 million home in Beverly Hills, Hamsher wrote he was “on his way to becoming the George Gobel of directors, famous for being famous.” And maybe famous for his quick fists as well. In a statement, Murphy said, “Jane and I knew ‘Killer Instinct’ struck a raw nerve with Quentin, but I was still caught off guard when he threw me up against a wall and punched me.” Hamsher, who was in the restroom when the confrontation occurred, said later Tarantino “should thank God Harvey Weinstein was there to save his ass.” According to sources at the scene, Weinstein stepped in and negotiated a settlement between Murphy and Tarantino — who had been put in an L.A. sheriff’s car following the incident. Tarantino apologized to Murphy, who decided not to press charges.