Tables filled with lobster, smoked salmon, shrimp scampi, caviar and red, white and blue pastries greeted an exclusive crowd of about 400 guests at a cocktail party hosted by Captial Centre owner Abe Pollin and his wife, Irene, before last night's gala entertainment at the sports arena. It was possibly the best spread of food laid out so far in this marathon of inaugural events.

"I've been a Truman Democrat all my life," said 92-year-old Washington liquor magnate Milton S. Kronheim. "But with this kind of food I think I'll become a Republican."

The VIP gathering in the Centre's Capital Club, which allowed guests not just a good supper but an escape from the clogged halls of the Capital Centre, where men in tuxedos and women in long gowns lined up for drinks in plastic glasses, attracted a number of Reagan intimates and cabinet members.

Several of the featured entertainers' wives held court, looking appropriately glamorous. Barbara Sinatra wore a ruffled black net dress studded with silver sequins, and Joanna Carson wore a wine velvet, fur-trimmed gown that looked like something Elizabeth I would have felt at home in. "I feel the luster of the White House has got to be enhanced," said Ed McMahon, who is here to emcee an inaugural ball and the 81 compainion balls across the country that will see the festivities in Washington by satellite. "The presidencey borders on royalty, and has to have that kind of influence. We are Number One and we should act like it."

Among the Reagan pals who attended were Robert and Betty Adams from Los Angeles, whose children went to school with the Reagan children. "I was at the Eisenhower inauguration and that was hectic," said Mrs. Adams. "It's so much more fun when you know the people."

Outgoing Republican National Committee Chairman Bill Brock said he didn't think people cared about the lavishness of the Reagan inaugural. "I think every four years we should celebrate," he said. "I think we like to look up to our leaders."

"We're going to get out of the despondency and into the hope and optimism," said art impresario Armand Hammer. "It's neat, it's really neat."