When State Department security people called Copeland's of New Orleans restaurant in Alexandria a few days ago to inform the management that a "principal" would be coming in for lunch yesterday, people got excited. The restaurant's general manager Bill French called his public relations adviser, Linda Roth, and both watched with growing excitement Monday, Tuesday and Wednesday as agents wearing earpieces and talking up their sleeves into hidden two-way radios checked out the kitchen, dining room and other corners of the restaurant.

French and Roth thought they were dealing with the Secret Service and ran down the list of possibles for the lunch -- presidential candidates, foreign dignitaries, a defecting Soviet agent, maybe even First Lady Nancy Reagan and her frequent luncheon pal, columnist George Will. Then yesterday, the security team swooped into the restaurant, taking three tables, but neither French nor Roth recognized anyone at the "principal" table. Roth quickly scanned a newspaper to see if any of the four men was an important new arrival in town. Finally, when one of the 13 agents came over to pay the bill, she thanked the manager and said the group had been there on a State Department training exercise. All that excitement for nothing.

Out and About Fashion designer Oleg Cassini has decided he likes harness-racing even though his professional debut wasn't auspicious. The 74-year-old fashion designer, who is the oldest man ever to be given a provisional license in harness-racing, finished dead last in his first race at Freehold Raceway in New Jersey Wednesday and fell off the sulky before a second race. Cassini had wanted to drive in a third, but a track doctor said his blood pressure was too high and ordered him to take the rest of the day off. "I didn't agree with the doctor," said Cassini, who blamed his accident on a nervous horse. "I should have raced" ...

Royal Watch: For all those people who express concern about how hard Queen Elizabeth II and her son Prince Charles work for the United Kingdom, it should be pointed out that they are quite wealthy. In fact, Queen Elizabeth is the richest person in Britain with a fortune estimated at $5.88 billion, according to the British magazine Money. Charles isn't nearly as well off yet. He is, however, the 14th wealthiest in the land he will one day rule with a respectable $600 million in assets ...

That was Las Vegas entertainer Wayne Newton at the White House yesterday. He stopped by with his fiancee' Marla Heasley, his daughter Erin and his father Patrick for a brief visit with President Reagan. The president thanked Newton for his "tireless efforts on behalf of American military men and women" ...

Denver Broncos quarterback John Elway is, believe it or not, coming to town tomorrow to receive the Quarterback of the Year Award at the Quarterback Club's annual awards dinner at the Washington Hilton. But for all those concerned Redskins fans, Doug Williams hasn't been overlooked. At the dinner, which is being sponsored by the Cystic Fibrosis Foundation, Williams will receive the Super Bowl XXII Most Valuable Player Award. It will be a football fan's dream night: About 25 NFL quarterbacks will be there to see the legendary Johnny Unitas and Bart Starr inducted into the Quarterback Hall of Fame ...