While representatives from the State Department were calling around yesterday to inform those invited to Secretary of State George Shultz's dinner for King Hassan II next Tuesday that the event was off, Time magazine was going ahead with a scheduled reception -- minus the guest of honor. The king canceled his working visit to Washington, which included a reception Thursday hosted by Time in recognition of a 20-page advertising section the Moroccan government had bought, which will appear in the magazine next week.

On Wednesday, the day that word began circulating that Hassan would not be coming because of health problems, the Time magazine invitations were being delivered. Among those invited to the reception at the Madison Hotel were the secretary of state, members of the House Foreign Affairs and Senate Foreign Relations committees as well as members of the Moroccan delegation and Moroccan Ambassador Maati Jorio. A spokesman for Time said, "This is a special occasion. We are still doing the special advertising section. Unfortunately, the king will not be here for the reception." Happy Birthday, John

At the same time all the Apollo astronauts were in town this week, Sen. John Glenn, the first man to orbit the Earth in the Mercury series, became eligible for Social Security. The Ohio Democrat showed up in the Russell Building for a committee meeting that was a surprise party for his 65th birthday, with "Happy Birthday" sung by Sens. Robert Dole, Robert Byrd, Howard Metzenbaum, Gary Hart, Joseph Biden and Barry Goldwater and Reps. Mary Rose Oakar, Dennis Eckart, Douglas Applegate and Louis Stokes.

Glenn cut into his 79-pound birthday cake, which included 30 pounds of chocolate and three bottles of Grand Marnier. The party-goers, who included Sens. Edward Kennedy, Patrick Moynihan and Sam Nunn and astrologer Jeane Dixon, were entertained by the Capitol Steps, rapidly becoming one of the city's most popular performance groups. Dixon predicted, "I feel a positive vibration about the upcoming (Senate) election . . . " That was not much of a prediction since Glenn is expected to be easily reelected to a third term, by more than 60 percent. Gifts to the Gallery

Things have been quiet at the National Gallery of Art since the "Treasure Houses of Britain" exhibition closed. But last night a small black tie dinner was held to preview the opening of "Gifts to the Nation: Selected Acquisitions of Mr. and Mrs. Paul Mellon," which opens Sunday and runs through Oct. 19. Mounted in the new galleries of the West Building, the exhibition will include more than 85 works of art selected from 822 objects the Mellons have donated to the gallery since their first gift in 1964.

Among the guests expected for the reception in the East Garden Court and dinner in the Sculpture Hall are Paul and Bunny Mellon, former CIA director Richard Helms and his wife Cynthia, National Gallery Director J. Carter Brown and his wife Pam, columnist Joseph Alsop, Assistant Secretary of State John Whitehead and collectors Thomas and Betty Evans and Ian Woodner. Out and About

Royal Watch: Andrew is going to have to keep an eye on that woman. Two "policewomen" walked into London's exclusive Annabel's nightclub Wednesday night and sat at the bar giggling and sipping champagne. Buckingham Palace was silent to any inquiries, but patrons of the nightspot could see beyond the blue uniforms and wigs. It was Sarah Ferguson and her close friend the future queen of Great Britain, Princess Diana. If the boys can have a stag party, the girls are going to play also. The queen probably was not amused . . .

The famous Harry Lund gallery on P Street is about to become a pet store, and on the second floor where Ansel Adams photographs once hung and sold for thousands of dollars, cats will be boarded. Time and progress march on, or something like that . . .

It would seem to be an unlikely couple, Nancy Reagan and the Rev. Jesse Jackson. But they have in common a concern about drug abuse. They spent nearly an hour discussing drug abuse at the White House yesterday. Jackson said later that he suggested they visit some schools together. The first lady's office said she and Jackson agreed "to stay in touch" and to urge Americans to take "a moral position to be publicly intolerant" of illegal drug use . . .