Mine is a fastback. And looks just like the pictures but the nut on the back was never spot welded there. I'm going to take a picture tomorrow. But as you can tell there is no way to slip a nut behind the hole without cutting a slot to fit it in. Thanks guys for your help and pictures. I'm going to have to think on how to fix this.
This month's Mopar Muscle magazine has a good article on exactly how to do that without welding. PM me with your cell phone number, and I will send you some high resolution pictures of the article.