Mastery and armor types

So I noticed the other day on my shaman that equipping different armor types didnt seem to affect mastery. I thought that they penalized you for not wearing 100% of your armor type? Did they remove this? If so Im headed to the AH to pick up some cheap epic cloth legs for PvE.

It is a passive Specialization to your class....does not effect mastery.

http://www.wowhead.com/spell=87507

ah crap 5%, thats too good to pass up =(