In yesterday's Style section, the place in the Capitol where a group of reporters watched "The Color Purple" playing on a videocassette recorder was incorrect. They were in the House Press Gallery. (Published 8/14/87)

It's not a story out of the neat, comfortable world of "Ozzie and Harriet," but it does involve their grandson. The battle for custody of the son of the late singer Ricky Nelson is turning out to be one of those confusing, only-in-Hollywood stories. Actor Mark Harmon, former star of "St. Elsewhere," contends that his sister, Kristin Harmon Nelson -- Ricky's widow -- is unfit to care for her son, Sam Nelson, 12, because of a prescription drug dependency. He wants Sam to live with him and his wife, actress Pam Dawber.

Yesterday, the boy testified in private at a custody hearing that he wants to live with Harmon. Earlier, a psychiatrist hired by Harmon testified that Sam feared his mother's drug-related "mood swings," which came on after his father died in a plane crash on New Year's Eve 1985. The psychiatrist said the boy portrayed his mother as a "dragon who wouldn't let him see his other siblings or family members." Harmon has been taking care of his nephew since his sister, a casting director who worked on the recent movie "Hoosiers," went into a hospital for drug rehabilitation treatments. The boy's grandmother, Harriet Nelson, 80, is expected to testify only as a last resort on behalf of her daughter-in-law in what promises to be lengthy, uncomfortable battle. Getting In Their Kicks

Monday night's celebration of the 5,000th performance of "A Chorus Line" ended up with a bit of a scuffle between producer Joe Papp and the show's coauthor, James Kirkwood, at a party at New York's Palladium. It was an evening dedicated to the memory of the late Michael Bennett, who conceived, directed and choreographed the record-breaking, long-running musical. In a speech about Bennett, who died recently of AIDS complications, Papp did not mention the show's other creators.

Kirkwood, who was stung by the omission, told Newsday he approached Papp at the party and said that not mentioning the names of the others in the show was "reprehensible, embarrassing and hurtful." He quoted Papp as replying with an obscene suggestion. With that, he knocked Papp to the floor and both began a round of fisticuffs. The following day, Kirkwood sent flowers to Papp with a note saying he would have made the same suggestion to him, but that he, Papp, was such a megalomaniac, "you'd enjoy it far too much." Out and About

When a political candidate has bigger ambitions, it is necessary to appear on television more, and that's not as easy as it seems. That's why Rep. Pat Schroeder spent some time recently with Dorothy Sarnoff, a New York communications consultant, who has been consulted by a number of on-air personalities as well as politicians. As one of Schroeder's staff aides explained yesterday, "Everyone needs advice on how to come across on television. We went up to New York to put a little more polish on the apple" ...

Sexy actor Richard Gere is out there in Cedar Rapids, Iowa, riding around in an old pickup and dressing like a farmer in blue jeans, a denim shirt, bandanna and seed company cap, and apparently he hasn't been recognized. He's there to film "Farm of the Year," and according to the location manager, Gere "look{s} more like a farmer than some farmers" ...

Exiled Chilean writer Ariel Dorfman will be able to return to his native land. Chile's military government has lifted the ban against him and 21 other political exiles. Dorfman was refused entry to Chile and put on a plane to neighboring Argentina Aug. 2 when he tried to return from the United States to start a new book. Dorfman, a U.S. resident, had said the military government had "re-exiled" him for his public criticism of human rights violations there ...

This is the big Ollie North weekend in Philmont, N.Y., home town of Iran-contra hearings personality Lt. Col. Oliver North. Philmont is having a parade, clambake, fishing derby and day of summer fun in his honor this weekend. The former National Security Council aide was invited, but his mother, Ann North, called the Philmont village clerk to say Ollie will be unable to attend. And to the surprise of no one who watched the hearings, the patriotic Marine declined "due to security reasons and on the advice of his attorney" ...

Signs of August: A group of reporters in the Senate Press Gallery standing around a television set watching "The Color Purple" playing on a VCR ...