RT Sent me to an RT dealer. Was quoted about $148 for the assy. I got the tail light assy out yesterday. Found a number on the back TMC Glo-Brite 182X. Crossed ref the number and found that many GM models (not the Express) use this assy. Dorman 1610049 Alt #5477868
More Information for DORMAN 1610049
For now I am going to try and epoxy mine, but if it doesn't hold, It's off to Rockauto I go.
Hope this helps someone else.