2006 TrailBlazer

Hello all. I'm trying to help out a friend with their truck. There is a piece that fits across the back up on top of the door. I think it's like a spoiler/3rd brake light type of deal. They were going down the interstate and it flew off and got shattered. I can see a nut on each side and double sided tape that held it on. The stealer wants $800 to fix it. Do you guys know what this piece is called or have a part number so I can look it up to replace it? Used is fine with me. Thanks ahead of time...............:rofl:

Anybody?

3rd brake lite housing, try a salvage yard as you said, of course ask for complete housing and lamp assy.