I just got a new wheelset (Easton EA70). It says its shimano 8/9/10 speed compatable (650c). I went to mount a new Dura-ace 10 speed 7800 casette. When i finished, I noticed an extra thin spacer in a platic bag, with instructions for mounting on 9 spd hubs. Does anyone have any idea if I was supposed to have used this, or is this just for hubs that are 9 spd only?

I guess I'll know when I test the wheel, but wondered if someone knew to save me the time of taking the wheel on and off if I did it wrong.