Pretty much this. It would suck if they did this at a scheduled show that people knew about and didn't advertise it as being nothing but new songs...but it being a secret show makes this kind of awesome.
They also played some super old songs. Most songs they played are more straight forward since there was no back ups on stage, just the three of them.
Hopefully their next album will sound like just three guys. I don't want them to make Dookie again, but I would appreciate a more stripped down Green Day album.