Yeah I think so as far as playing, I've seen people brought up to play guitar on Knowledge at Nimrod shows but can't recall seeing it during Dookie/Insomniac. Then during Warning they expanded it to creating a whole band. I have also seen them bring people up to do random stuff during pre-Dookie shows though, can't think which ones but I can vaguely remember one where they got two people to act something out or something? Wasn't a regular thing but they did sometimes let people on stage or involve people during more informal/unplanned early shows.