The little Futaba 'spectacles' should be kept in one piece. You'll see that there's a notch on one long edge that goes against one of the little plastic braces on the servo. The little raised 'spectacle' pieces are put on face-down so that the raised pieces of rubber push into the screw holes i.e. you shouldn't be able to see the raised rubber circles after fitting them to the servo.

Cheers,
Neil.