You didnt get what they were saying. Its an lbz if its an 06, it just has a diffrent tune in the ecm which im sure your gonna change anyway. Buy it if it's clean and in good shape...
You'll love the lbz. I had and Lb7 that was stolen at nhrda then picked up an 07 lbz and my brother has an lly. Lbz is byfar my favorite out of the three.
And then some....when you get it tuned you'll have way more HP than it ever did as a stock LLY/LBZ. If you like the truck then just pull the trigger on the deal. It's a good truck that should hold it's value well.