CF6-80 Series motors have the #1 fan blade "1" stamped each side of the blade dove tail post on the fan disc. You cannot see it with the spinner on. counting is counterclockwise looking aft and i believe #5 blade is also marked on the spinner disc. my old company used a paint mark on the spinner to indicate#1 fan blade not to be mistaken for the paint mark on the spinner offset hole. This ensures that the spinner goes back onto the correct position on the fan disc. High N1 vibs on these engines was usually corrected by lubing the fan blade dovetail posts on the fan disc as well as lubing the fan blades.