96 Deville battery tray

I installed a battery for a customer of mine in her 1996 Deville. I do handyman work and her car battery was dead. When I took out the old Delco, half of the battery tray was rusted through. The "wedge" hold-down and bolt are still attached to the piece that came off. I want to install a new battery tray and was wondering if anyone had doen this before. I can't tell if the tray is/was bolted in or actually welded in production. Can't see how the original was installed. Any help or ideas appreciated. Mitch

It should be welded in place...

That's what I thought. That battery is really tucked in there. A huge car with a giantic engine compartment and the battery is put in a very small space. The change took a lot of work. I had a pile of bolts and parts before I even got to the battery. Thanks for the input.