Which Came First? The Story or the Joke?

In 1992, author Rabbi Joseph Telushkin published "Jewish Humor," which, at pages 45-46, includes a joke about a man who applies for a job as the shammes (sexton) of a synagogue but is rejected because it is revealed that he is illiterate. He then goes on to become wildly successful in business. He is granted a large loan by a bank, the manager of which notices that he has signed the loan document with an "X" and asks him what he thinks he could have accomplished if he were able to read and write; he replies "I would be the shammes of he Rivington Street synagogue." This is the plot of "The Verger," one of he Trio originally published by Maugham as "The Man Who Made His Mark." Which came first - the joke or Maugham's story?