My car was missing this when I got it.
Also, my coolant tank/battery tray was broken, and I replaced it.

I tried to get a clamp, but I can't find one that fits. I got two from Amazon and one from eBay, and they were all too big, even though they are all listed as being for the Camaro. It looks like any normal GM clamp should fit, but doesn't, because there is that outer rim on the tray.

The battery fits the tray exactly, so I don't think it's oversize. The tray is from Dorman. Did Dorman screw something up here? Do these cars have a special clamp? Am I just completely out to lunch here?