Embarrassing disclosures generate publicity, and publicity sells books. So former White House spokesman Larry Speakes ought to be doing pretty well these days with his kiss-and-tell volume about his days in Washington.

But after the furor is forgotten and Speakes has banked the last dollar from his literary efforts, it's hard to believe the former press spokesman for President Reagan won't find he is a big loser from this episode.As the public is well aware by now, his book "Speaking Out" discloses that on at least two occasions Speakes manufactured quotations for President Reagan once after the Soviets shot down a Korean jetliner in 1983, and again at a U.S.-Soviet summit meeting in Geneva in 1985.

Neither of the quotes amounted to much. In the first instance, Speakes put a comment from Secretary of State George Shultz in Reagan's mouth, and in the second he made up a quote. In neither case did he check with Reagan. In both instances the aim was to bolster the president's image.

Though the disclosure makes President Reagan look bad for letting his press secretary put words in his mouth without even bothering to check with him and not even finding out about the incidents until Speakes' book came out, the worst wound is still the one that Speakes inflicted on himself. The bad judgment that Speakes displayed in manufacturing the presidential quotations was compounded by his decisions to brag about his folly in print.

Speakes may not have heard the last of this episode. Imagine how the Wall Street firm that employs him as a spokesman must feel about the disclosure that Speakes has no qualms about putting words in his boss' mouth.