President Reagan didn't happen to mention it when he was discussing his New China Policy the other day at his White House press conference, but there's more new china on the way.

Some of it will be a gift to the Reagans for use in their personal entertaining so their friends won't have to eat from mixed sets either. (Reagan told reporters that "the truth of the matter is, at a state dinner we can't set the tables with dishes that match. We have to have them mixed . . .")

Featuring hand-painted American garden flowers, the 120-piece service for 24 will be called "Nancy" and could be the prototype for similar sets to be sold later on the retail market.

Another line of china, inspired by roses in the White House Rose Garden, will be sold commercially as commemorative pieces. A new edition is scheduled to come out annually for eight years. Part of the proceeds will go to the White House Historical Association for refurbishing and acquisitions.

All of this new china is coming from the studios of Edward Marshall Boehm Inc., of Trenton, N.J., and Malvern, England. That's the firm that makes those animal, bird and flower sculptures that American presidents have been giving to foreign leaders for the past 20 years.

Helen Boehm, the dynamic chairman of Boehm's board who built the firm into a multimillion-dollar-a-year international concern, says Nancy Reagan has seen the design and is "thrilled" about the new china that will bear her name.

"And it's not going to cost anybody any money," says Boehm, whose other endeavors include having her own polo team. "In giving, you know, there's such a beautiful feeling."

A White House spokeswoman says, however, that Mrs. Reagan wants to buy the set. "She is very flattered that Mrs. Boehm is naming it for her," says Sheila Tate, the first lady's press secretary.

Billionaire Saudi financier Adnan Khashoggi's idea of a joke probably wouldn't get many chuckles out of the Pentagon's top brass, but everybody who was in on it agreed later it made a smashing ending to a spectacular evening.

"I'm kidnaping all of you and telling your country it can get you back for $1 billion," Khashoggi told a group of very nervous U.S. Navy pilots who were visiting his yacht in the Bay of Naples not long ago.

These were no ordinary pilots. They were from the squadron on the USS Nimitz that had shot down the two Libyan planes over the Mediterranean.

"You should have seen their faces. You could tell they didn't know what was going to happen to them," says Hollywood actress Melissa Prophet, a guest of Khashoggi's when the pilots from the Nimitz dropped in to visit the $80 million lavish yacht, Nabila, featured in the current edition of Architectural Digest.

Actually, Khashoggi could not have been more hospitable once he realized who his callers were. He ordered tours of his vessel and the kind of red-carpet treatment usually reserved for royalty. Then, insisting that they stick around for dinner whipped up by his two French, two Chinese and two Arab cooks, he had his captain quietly haul anchor. Not until the dining room draperies were pulled back did the Americans know the Nabila was circling the Nimitz and that Khashoggi wanted to take them to Sardinia for three days.

Everybody declined, of course, and danced away their sorrows in the yacht's mirror-ceilinged discotheque, operated by a full-time French disc jockey. As going-away presents, Khashoggi gave the Americans those chic, long, white, high-necked, wide-sleeved cotton gowns. In exchange, using their own U.S. Navy wings, the Americans "pinned" several of Khashoggi's shipmates, including his year-old son Ali.

"All summer we had the most beautiful people on board, but none of them -- not Valentino, not Zeffirelli, not any of them -- was as much fun as those guys from the Nimitz," says Prophet, whose father, entertainer Johnny Prophet, has known Khashoggi since his Las Vegas days.

One American officer was so startled to find Melissa Prophet aboard, having seen her the night before in the movie "Van Nuys Boulevard" on the Nimitz, that he asked Khashoggi for her hand in marriage.

Nancy Reagan may be responsible for a revival in portraiture among women of a certain age. Ever since the Women's National Republican Club of New York City hung the portrait it commissioned of her in its West 51st Street clubhouse, celebrity portrait painter Zita Davisson claims she's been swamped by women over 50 wanting similar treatment. "It's quite a switch," says Davisson, who worked entirely from sketches and photos of the first lady. "They're the same ladies who used to tell me that if only they were 20 they'd have me do their portraits." Before Davisson will paint them, she sends them a fact sheet. Among the do's and don'ts: Wait six to 12 months after a facelift.

Occidental Petrolem's Armand Hammer, who was sworn in yesterday as head of President Reagan's three-man Cancer Panel, need never have a doubt in the world about what money can buy. Recent example: The $1 million Arabian stallion El Paso, which Hammer and two partners bought in Poland this summer -- the same horse the Polish government said it wouldn't sell and that money couldn't buy.

The paintings were reproductions, but even so the effect was sensational, says Gladys Gaviria, wife of Colombian Ambassador Fernando Gaviria. Their embassy residence at 20th and Connecticut will "star" briefly as the Pittsburgh mansion of Andrew Mellon in a docudrama of his life, first in a Public Broadcasting System series, underwritten by Conoco, on great American art collectors and the museums they founded.

Mellon's Washington apartment was in what is now the headquarters of the National Trust for Historic Preservation on Massachusetts Avenue. Recreating that setting wasn't easy since only one photo of Mellon's apartment existed, a view of the multimillionaire banker standing in front of a fireplace.

The apartment plays a key role: It was there Mellon and British art dealer Lord Duveen struck a deal for $21 million worth of art that would become the nucleus of the collection Mellon used to found the National Gallery of Art. Duveen was so determined to sell the paintings to Mellon that he rented the apartment below him, filled it with the art, then left the key with Mellon while he went out of town. Night after night, armed with a flashlight, Mellon would slip into Duveen's apartment to gaze at the paintings. Unable to stand it any longer, the Pittsburgh banker finally invited Duveen to a showdown lunch in his own apartment.

It fell to Paul Mellon, son of the philanthropist and himself the guiding light of the NGA's East Building, to reassure series producer-creator Byron McKinney (he also created "To Fly" for the Air and Space Museum) and director Dewitt Sage that the apartment was both authentic and convincing. Mellon paid a visit to the set the other day, then surprised everybody by sticking around long enough to have his picture taken with Remak Ramsey, the actor who portrays his father.

Billy Carter writing a column on the state of the nation for Oui magazine? Yep. And in the December issue, the first of his monthly efforts appearing under the title "Redneck Reason" will be a discussion of that other apostle of Good 'Ol Boyhood, the Rev. Jerry Falwell and his Moral Majority.

Managing editor Dian Hanson says it's vintage Billy -- opinionated and earthy. Bought from Playboy by Goshen Press of New York for a reported $1.5 million, Oui once aimed at an international audience but is now appealing to readers looking for their American roots.