It's an S-O, worth about $300.00. You can distinguish it from a vintage style O in that it does not have position markers on the fretboard. The rosettes are also a bit different.
That's the one on CL Orange County!! Trust me, if it was vintage and worth lots, someone on this website would have drove long ways to pick it up. Some people have RSS feeds to let them know when ukuleles are posted. Good luck in finding one as lots of us are searching CL for the next great find. haha