Oh no Otto! Those tail lights are extremely tough to find. Each year and sometimes multiple times a year the tail light assembly was contracted to different manufacturers. I had the plastic snap where the screw meets the red portion and I had to replace the entire assembly. They don't sell the red plastic or the metal portion. You will need to buy the entire assembly unless you are lucky enough to find someone with the exact rear portion. If you go online there are at least 4 or 5 version or rear GT tail light assemblies. Some have a flat portion on the bottom, one is more square, one looks like more like homeplate on a baseball field- Pain in the bum
As soon as I resolve more pressing problems that's one item I'm going to modify to get away from the inability to replace the stock setup.