The ignorance of dealers, it sometime amazes me.
Yes, it is the same part number for the new rails as used on 2007 H3s. It is the same part! The bulletin clearly states 2006 H3 vehicles. Does the dealer think that all new part numbers are issued for each new model year vehicle? Hell no...they are issued for each new part release, and if the part(s) is carried over for a new model year, it will have the same part number.
Tell the dealer to read the damn bulletin or you will be reporting him to Hummer customer assistance, and if you get a JD power survey, you will note on the survey the dealer is an idiot.
The part was redesigned to correct a problem (cracking), and the new part is supposed to be more robust and not supposed to crack. Therefore, GM will carry the same part over and use in on the '07 vehicles, and they might use it on the '08 vehicle. Probably 75% of the parts are the same number between the two model years.
Sorry for the ranting, and I'm not ranting at anyone on the board, but I had a few conversations with idiot dealer service managers today, and I'm truly amazed that any of them can wipe their arses with two hands and a mirror.