The combatants both know the identity of their opponent. But seeing as G0-T0's opponent is 'Darth Plagueis' and not 'Hego Damask' then G0-T0 will not be aware of his opponents alter ego unless he sees his face. Plagueis is aware however that G0-T0 is a droid.
Then this will be interesting. This will allow Plagueis to operate in plain sight without G0-T0 being the wiser. Plagueis can easily find G0-T0's yacht. All he has to do is capture some exchange thugs that have access to the yacht (this is the hard part) and torture them for information. Once he finds a thug with the proper information, he lures G0-T0 into a trap. He uses a decoy vessel to distract the yacht while an armed vessel (possibly pirate) destroys the ship. Unless G0-T0 can transmit himself to a droid that's not on the ship, it's game over.