That site on Amazon says they do not fit an 08 Sky. FYI
I've had GM part sites ran by GM dealerships say that parts that fit our car don't fit our car because they haven't properly cross referenced them. LOL It's not uncommon.
Knowing what other cars share our parts is a huge help when it comes to this stuff. Like MM said, if they fit a Cobalt they'll fit our cars. The door handles on my car now are not "Kappa" door handles but were made for the Cobalt. I got them because they were more reinforced than our stock handles and came ready to paint...