This film was among the first "made for television films"... but it's actually a compilation of the first three episodes from the television series all filmed 3 years before. They were... "Enter the Lone Ranger", "The Lone Ranger Fights On", and "The Lone Ranger's Triumph".
The music in this film is actually the work of several classical composers. The well-known main theme is actually the climax theme (overture) from an opera called "William Tell" by Rossini. Also heard in the film are fragments from works by Tchaikovsky and Wagner.