Dave says he went and saw Book Of Mormon and then ran home and cranked out the record with John 5. Book Of Mormon is a Broadway musical. And Dave's own words say he wrote a musical and then talks about how it's the story of his life lol. He's saying its a Broadway musical album that would be the music for the show.
Now, having said that, we're talking about Dave saying all this. It's probably all bullshit. But that's what he said and he couldn't have made it any clearer, what he said the record was. Does that mean that's what it is? Hell no! The guy says whatever he thinks people want to hear.