Not sure on your XM, but for my XP, I used a combination of the factory Skidoo spacer and added washers (one heavy, one light) to make the change. I think that the change over is a straight fit for the US measured Gripper (2010 and earlier) skis, except you will need a longer bolt.
Things to watch-- the Gripper skis were US until 2011. Newer ones are metric. I had a US (3/8) Grippers. My 2010 Skidoo uses metric, so I needed to stay with that, for the ski leg bushing diameter.
Bonus tip:
I didn't have the Polaris factory ski insert bushings. Solved it in the hardware store little pull out bin/drawers:
3/8 x 1/2 x 1 inch steel spacer inside a
1/2 x 5/8 x 1 inch steel spacer topped off with a
9/16 flat washer.
On the newer metric grippers, you need ream this repair spacer from 3/8 to 10 mm with a 13/32 bit, which made a hole about 10.3mm. There, you just saved about $38 per ski on the insert bushings.
