I don't fly long haul as many as other FTers, but here are the gates my CX's NA flights departed from in 2009 and 2010. Granted they are all afternoon flights so there may be a difference with your red-eye.
July, 2009: San Francisco: Gate 60
December, 2009: San Francisco: Gate 64
July, 2010: Los Angeles: Gate 21
So make sure you check your gate number as they can be everywhere.