well im a concrete finisher and i can tell u first hand it needs a moister barrier. have done it both ways and the floors that dont have the barrier will always sweat. the only reason a finisher will tell u it dosent is drying time he will get done quicker if it does not have the plastic.
dont try to resurface it. it will just come off later on it will not bond that well to the floor. what more than likley caused the pitted floor is salt from the roads that melts off the car.