Well, all 3 spacers aren't the same length. Two are the same and one is a longer.

 

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Drivers side, Passenger side on a motorcycle? Huh?

Please allow me Sir.
If you are sitting behind the steering device of a motorcycle, a car, boat, airplane, etc. Then when looking forward, that determines the left and right side of the vehicle.

Check the drive belt on your rear wheel pulley. Is it centered? If so your probably good.
Look at each side of the drive belt, is there excessive wear on either side? If not then you're good to go.

 

More critical is the Right side ... Rotor to Caliper Alignment


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Photo of them will help, since two of them should have the seal wear marks, and the one without seal line marks, is the one that goes on the outside on the primary side.