What if you obtained a marriage licence prior to prop8 and were married to a person of the same sex after it was passed?
It wasn't legal, unless the marriage was solemnized before the
passing of Prop 8. The license just gave you the right to marry,
but the actual ceremony and having it registered is what makes it
legal, and during the Prop 8 era, no weddings could be held.
But if the marriage was registered, then you were legally
married in California. You would have also been part of a lawsuit
before the California Supreme Court.