Well, no. But I'm about a third of the way through and I'll give you my impressions.
I love the Supernatural novels for being able to go places the show can't afford to go. This book so far is taking place in 1950s NYC. The boys have been sent back by another angel to rescue some scrolls that were stolen from an auction in 1954. Can you imagine our boys in that era? Sam was told to get a haircut! And he has to do research at the actual library. Their money doesn't work--too modern looking--and of course, neither do their phones. Dean gets a job as a bellhop in the hotel from which the scrolls were stolen--and his uniform comes complete with a hat with a chin-strap. All that is kind of neat.
BUT I don't feel like the writer has our boys' voices down. One of the first books did, so well that I could hear Sam and Dean talking. But this--not so much. The rhythm is just off or something. I can only imagine how hard it is to write stories for another writer's creations, and to keep up with the mythology. While the story's good, it doesn't sound like Supernatural.