The Sacramento Bee - 4 Nov 1988 (pay-per-view) quotes in a list of concerts for the night "I-Beam in San Francisco for what is being billed as the 'return' of Faith No More."
The review of a "recent" Faith No More gig in BAM Magazine 2nd Dec 1988 by Steffan Chirazi (who wrote the Faith No More biography "The Real Story") mentions introducing the new singer, broken cameras and a bad crowd reaction, all points known from interviews about Patton's first gig.
All evidence points to this November gig being the only pre-Real Thing Patton gig.
Michael Franti of the Beatnigs doesn't remember playing with Faith No More. Both flyers refer to Faith No More playing with Beatnigs, however the advert on the day in the gig section of BAM Magazine doesn't mention Beatnigs so it is possible Beatnigs didn't play the night.