Seems to me on those shows there is only one band member that get talked to for anything more than a single comment to make the host look clever or funny. James Corden has Reggie Watts and every night he speaks to him but I've only even seen him talk to the drummer when he has a smart arse comments and until the other night I'd never heard him introduce the band. Paul Shaffer was on Letterman for years but I don't know who else was in the band. And only last year there was some other big metal player on one of the night shows I can't even remember the show or the muso but I know Blabber and MI raved about it for a few days before it died off and became a no news event. As much as I like Gene I can't see his stint being anything but an introduction on night one and little more than a few fast cut shots during the week. If he's lucky they'll get him to throw a drum solo in but I wouldn't watch the show just for that, it will turn up on YT, or his own site.