The top shock bolt is a clevis. It can't turn when mounted. Check out a shop manual or just look for the upper shock bolt on ebay or at an online vendor and you'll see.

 

I went ahead and shimmed it 5mm. Noticed the top shock dosen't rotate from the bottem so there shouldn't be anything to worry about. Bike feels much better so far. I have a long bolt stock so I could fit at least another 4mm of shim in there before running out of threads.

 

Kewl