Is the package tray on the 78-80 regal different

[SmooveG]

I'm trying to install a 3rd brake light on a 80 regal and it's not working.
no room. My package tray must be shorter.

 

[turbofish38]

It should be the same as long as it's a 2 door coupe.

 

[SmooveG]

That;s what I thought. Maybe I have the wrong third light. It hangs half way off the package tray