In his 1993 interview for Flipside #83, Beck is asked if he's played at Jabberjaw. He replies "Yeah, last month with Dos and Possum Dixon. It was great."
Unfortunately, I can't find the actual date for this show.
dos was a band by legendary punk bassist Mike Watt and his (at the time) wife Kira Roessler (also a well-known punk bassist).