rear tail light panel on 70 Mach I

[automart 10]

After my restorer quit on my car, I carried it home in a box. I had another restorer finish the paint, hang doors, etc. anyway, I put the rear tail lights in and the right one would not go in without removing the RR extension. Anyone ever had that problem? Was it welded in incorrectly or just a bad aftermarket part.

 

Any suggestions?