My kitchen faucet rusted loose

My original flat-washer (or flat bar?) brackets rusted off my delta washerless kitchen faucet. I'd like to get a couple of these bell shaped brackets instead:



I see it is labeled "bracket". What kind of bracket, and where can I get them? The "bells" would be big enough to go over the top of the old, rusted nut and I could spin new nuts on to tighten the faucet back into the sink.

The original brackets have simply crumbled away. Am I correct in not wanting to disturb the original nuts? I'd hate to damage the mount rods by trying to loosen rusted on nuts if I don't have to.