User blog comment:Thailog/Ep. 201 "Happy New Year!" discussion/@comment-3118271-20120502182105/@comment-1038387-20120502191850

Yes, Freddy is Captain Marvel, Jr. Because he got his powers from Billy, he doesn't shout "Shazam!", but "Captain Marvel!". Which is why he can never introduce himself by his superhero name. He went by CM3 for a while.