Sounds like a uds. Stainless really isn’t necessary, just fights off rust on the outside a bit...the inside is still gonna be black after a few smokes. Either weld some tabs inside or the above bolts should work just fine.
I recommend using the cheap shelf brackets from Lowes/HD etc. Just tack weld 3 of them to the inside of the drum. The actual shelf supports can be cut down to about 1 1/2-2 inches long and allows you to adjust the rack height as needed. Also makes it very easy to add additional racks. Not a great picture but you can see how i did it on mine.
Current Smokers, Brinkman ECB, Masterbuilt 30 Analog, SmokeHollow Pro44, Home Built 60gal RF, UDS
Nothing wrong with being stupid as long as you know you're stupid, it's when you're stupid and don't know it that you become dangerous