What accounts for the 1920s hit parade at the Kennedy Center these days? In the Eisenhower Theater, we have "The Last of Mrs. Cheyney," a 1925 chestnut of a drawing room-mystery that has since hauled itself through a number of stage and screen versions. The Opera House next door has the 1926 George and Ira Gershwin musical "Oh, Kay!" frantically being cut and revised since its unheralded opening here.

Both shows are about the humorous rich, that fictitous class of people bumbling about in elaborately furnished sets, wearing fancy clothing and uttering expensively sophisticated thoughts."Mrs. Cheyney" also has Deborah Kerr who, however much she points to her other genuine theatrical achievements, is still the fastest stage lady there is with a teacup or stemmed glass.

Neither "Mrs. Cheyney" nor "Oh, Kay!" however, has that fizz that one expects when opening such old bottles. To change metaphors from Champagne to clothes or antique furniture - these all being highly important elements in such productions - they got by originally on stylishness, but the material of which they were made is not very good and, after years in the attic, is full of holes and creases.

It's easy to sympathize, however, with the hopes of the people who revived these shows. After years of social drama and then psycho-drama, a little wit, drama, color and rhythm seem tantalizing. These particular oldies, however, offer too little. They are being dug up because one can't keep on doing. "The Importance of Being Earnest" forever, we are down to the minor plays of the era. Attempts to write new '20s comedies, such as "Gracious Living" earlier this season, are even flatter.

So we are in an awkward time until someone finds a new way to bring the old theatrical values to the stage. Add to that the often lamented problem of the lack of plays for middle-aged actresses - Deborah Kerr and Ingrid Bergman, who commendably want to be true to the stage year after year, are down to the bottom of that barrel - and you have. "The Last of Mrs. Cheyney."

It has picture hats, parasols and silk dressing gowns. It has lines like "If a man is prepared to give such pearls to the woman he married, what would he not give the woman he loved?" It has four different "House and Garden" sets. It has Deborah Kerr spending two hours with her eyebrows in an interrogative position while her mouth is smiling, the stage expression of upper class cynicism which must be very wearing to keep up.

It just doesn't have - kick.

THE LAST OF MRS. CHEYNEY - Kennedy Center Eisenhower Theater through Sept. 30.