Is there a washer on the bolt - Dura Ace 9000 brake caliper?

[NHAero]

Building up the Firefly with a set of used 9000 calipers bought here, the front has a washer on the mounting bolt, the rear doesn't. Shimano instructions don't show whether there is or not. Information please...

[NHAero]

Pix on ebay show a knurled washer front and rear...

[jtbadge]

Yeah, don't you need the knurled washer to prevent the caliper from rotating with relation to the frame?

[oldpotatoe]

Building up the Firefly with a set of used 9000 calipers bought here, the front has a washer on the mounting bolt, the rear doesn't. Shimano instructions don't show whether there is or not. Information please...

Use a knurled washer there. Helps to keep it tight and centered.

[NHAero]

Thanks much..