The late DeWitt and Lila Acheson Wallace, cofounders of Reader's Digest, might have been a bit embarrassed by all the hoopla that went into dedicating the DeWitt Wallace Decorative Arts Gallery here Saturday night. "They were gentle, unassuming people who loved Colonial Williamsburg," said U.S. Chief Justice Warren E. Burger, who presided at the banquet at the Williamsburg Lodge attended by about 300 friends of the Wallaces. "They never liked to draw attention to themselves."

Laurance S. Rockefeller agreed with Burger and so did George V. Grune, chairman and chief executive officer of the Reader's Digest Association. "For nearly 50 years, they had a secret love affair with Williamsburg, coming and going very quietly, but enjoying themselves immensely. That was their way," said Grune.

Rockefeller, whose family has shared many philanthropic projects with the Wallaces, said he didn't believe that "we could have gotten Wally DeWitt to come to something like this," referring to the gala gallery opening. The event featured remarks from what Kevin Roche, the internationally known architect who designed the gallery, termed "an embarrassment of speakers."

The invocation was delivered by the Rev. Norman Vincent Peale and the keynote address by Robert McCormick Adams, secretary of the Smithsonian Institution.

Although some observers have dubbed the building a "nonbuilding," Roche said he did not view the building "as anything unusual or exceptional. I don't feel very eccentric. I love nonbuildings. I wish there were more of them."

The Wallaces contributed $14 million of the $17 million necessary to build the new gallery and reconstruct the Public Hospital for Colonial Williamsburg. The public hospital building of 1773 is immediately in front of and partially hides the gallery building, which looks simply like a 12-foot-high brick wall from the street.

J. Carter Brown, director of the National Gallery of Art, one of the many prominent guests on hand here, said, "This has national significance in that it is a recognition of the importance that the decorative or folk arts play in our history as a people."

"I went to visit the Wallaces at High Winds their home and told them that the project would require at least $12 million, three times more than the $4 million leadership pledge that they'd already agreed to," said Carlisle H. Humelsine, chairman of the board of trustees of the Colonial Williamsburg Foundation. "Mr. Wallace didn't gasp, but turned to Mrs. Wallace and said, 'Lila, this is a fairly heavy sum for me to handle at this time. Would you be prepared to help me?'

"She answered: 'No, DeWitt. While I'm fond of Williamsburg, you know we never share projects.' But she added, 'We'll talk about it, the two of us.' "

The result was that the Wallaces made the gift and in addition set up the DeWitt Wallace Fund for Williamsburg, to which he made a gift of Reader's Digest stock that is producing an annual income of approximately $600,000 for Colonial Williamsburg.