Yes, it does. Also, be sure to keep up with the discussion in the Brewmaster tanking thread: I actually answered this exact question in the (currently) most recent post:
Originally Posted by Kisho
The set bonuses are pretty amazing. Personally I would (and did) drop a bit of ilevel to get the 4 set bonus. I wouldn't be able to tell you exact values, but remember that our 4 set also affects the Guards from our Ox Statue, making it a pretty significant raid 'healing' bonus as well.