Yep...looks right.
I found this 09 exhaust on ebay:
http://www.ebay.com/itm/09-HUMMER-H2...ht_2916wt_1396
If you look closely at that second picture you can see that the muffler is stamped with G4-4152 2 343 8 A. I get nothing when I Google on that stuff either. So, maybe those numbers are more like 'lot' numbers used during a production run or something instead of a 'part number'.
Dunno...just a thought.