Jeff and John, who wedding I went to last night, was presided over by a SF judge, and is as valid, as any marriage between Jeff and Jennifer. 100%. And even if they pass that stupid amendment, which they will not, its still a legal marriage, for better - but most likely, for worse.
And yes, it was the exact same contract I signed, it just says party A and party B, and not Bride and Groom. And if you remember your Constitution class, you will remember that that 'no ex post facto' law can be passed, so even if the amendment is passed, the weddings that took place are still valid.