SHE WAS wearing a Secret Service identification button on her lapel, but that wasn't a woman agent running interference alongside First Lady Rosalynn Carter at the Kennedy Center Tuesday night.

That was White House chief of staff Hamilton Jordan's ex-wife, Nancy.

She is so seldom seen in public that most reporters and photographers waiting for Mrs. Carter's arrival at "West Side Story" didn't recognize Mrs. Jordan.

Mrs. Jordan's exact status at the White House has been clouded in mystery since her divorce in 1978. For a time, her duties were described as those of an unpaid volunteer.

Then, she reportedly went on salary. Asked last week how much Mrs. Jordan earns, a press spokesman in the First Lady's office declined to answer, saying it was Mrs. Jordan's private business even if public money was involved. She referred the call to Hugh Carter, the president's budget overseer.

Carter said he didn't know why anyone on the First Lady's staff expected him to answer the question. He never gets involved in the First Lady's business, he said. "They're very sensitive over there on that subject," he added.

All White House staff salaries over $40,000 are considered public information, he said. Mrs. Jordan makes less than that.

Reminded that "under $40,000" could be anything up to $39,999, he said: "I assure you it's much less than that."

The other night was the first time reporters who regularly cover Mrs. Carter recall seeing Mrs. Jordan as part of her entourage.

Hollywood's Sol Laykin, court jeweler to practitioners of the political and performing arts, loves to talk about his successful deals.

But one failure was an attempt several years ago to persuade then First Lady Pat Nixon to let him sell a $100,000 cat's eye surrounded by diamonds which had been given to her by "an oriental potentate."

She thought about it and then declined, Laykin says. "Of course, it was given to her when her husband was vice president -- before the law was passed that you couldn't keep such things."

Meantime, members of former President Ford's family have turned into good customers. Betty Ford recently got a gold bracelet and earrings . . . "little things." Daughter Susan and her husband got "a steal." Laykin contributed jewelry to a silent auction, the procedes of which went to charity, where Susan bought her husband a $9,000 watch (made from a $20 gold piece) for a bargain $5,800 bid.

White House chief of staff Hamilton Jordan's buddy Nathan Landow manages the building at 1601 18th St. where Hamilton Jordan's buddy, John Golden has just moved himself and his consulting business.

The building belonged to Landow's late father-in-law, and Landow is the estate's executor.

If they can locate the tree, maybe they can make it into a monument.

When Ronald Reagan was a high-school lifeguard, friends say, he saved 60 lives.

Everytime he pulled someone from the Rock River, his old chums recollect, he swam out and carved a little commemorative notch in the bark.