I have had 2 C6 coupes. A 2006 and now a 2013. All C6s have the one piece removable roof as standard. The LS2 engine from 2005 through 2007 and the LS3 engine from 2008 through 2013 are the same targa roof setup. The biggest difference is that for late 2005 and 2006 GM changed the composite adhesive for the roof which was not sufficient. My 2006 roof started creaking and making popping noises due to delamination of the layers of the roof and the adhesive. Chevy replaced the roof under a factory recall and the dealer then repainted the solid color roof to match. This was not the case with the smoked top, only the body color roof panel. There have been no problems from 2007 through 2013. BTW, I was surprised when I received my 2013 in that it had all kinds of 60th anniversary emblems all over the car.
Good luck with your C6. It's a great car and hope you enjoy it as much as I have.