It's definitely not all pre-recorded. Obviously they're playing to a backing track but you can clearly hear the live tracks and their little quirks compared to the backing track. I don't know how obvious this is to a random, but as a musician that stuff sticks right out to me. The only thing I can't pick out clearly right now compared to the backing track is the guitar, but I've not listened to more than a few snippets yet so that might be clearer when I get a chance to listen to more (but it's also much easier to mix a live guitar to blend right in with the backing track if the guitarist is tight enough than it is to do the same with vocals).