Hmmm. The Internet Broadway Database lists a musical comedy called "The Blue Moon" that was performed in 1906-1907--which is the right time frame--but (1) it lists all the songs, and they don't include DON'T GO IN THE LION'S CAGE TONIGHT; and (2) it give the following credits: "Music by Howard Talbot and Paul A. N. Rubens; interpolated songs by Addison Burkhardt and Gus Edwards; Book by Harold Ellis; Lyrics by Percy Greenbank and Paul A. N. Rubens; Musical Director: Albert Krausse" --and those don't include Gilroy and Goetz.

Surely there weren't TWO plays with the same title being performed in the same year, do you suppose?