Will Liberace's chocolate piano play the White House? The question of how to give Ronald Reagan a chocolate piano with white and dark chocolate keys, real gold leaf scrollwork and monogram and truffles where the strings should be occupied Liberace yesterday in between his opening performances at the Kennedy Center.

In these days of bomb squads and metal detectors, you don't just send a get-well-soon gift to the president precipitately. At last report, Liberace planned to call his old friend, Charles Z. Wick, head of the United States Information Agency, for advice. When Wick was a professional piano player, Liberace's manager, Seymour Heller, was Wick's agent, too.

That the piano is still in one piece surprises the Watergate staff. When Liberace didn't order room service breakfast and wasn't seen in the hotel restaurants, some thought he probably ate the piano for breakfast. Marc Randolph of the Watergate Pastry Shop took three days to make the hotel's gift.

"Liberace didn't touch a truffle," said Dan Langan, his publicist.

"He had a truffle. He loves chocolate," said Heller, his manager of 35 years, "but not for breakfast."

"He ate his usual day-of-the-show breakfast," said Langan: "Juice, coffee and vitamins."

Monday night, the Watergate staff members were congratulating themselves on having provided lavishly for Liberace. And then the phone call came from the suite: please send up a whole watermelon. Nobody had thought about watermelon, the Las Vegas diet. The kitchen didn't have any watermelon. Undaunted, they sent over to the Watergate Safeway and bought a watermelon.