I called Dishmaster and explained what I was looking for. I viewed the online diagram so I could identify the parts. The rep was very helpful verifying which parts I would need. It arrived, the plumber came back. All is well!
We dropped one behind the cabinet and it rolled underneath so we had to get a new one. Ridiculous shipped costs. They should have an option to mail it in an envelope.
P1283 Flange Nut