Here are some from a Retro Bird site:
High $. I don't like the newer design Thunderbird as well as the old.
I think those are Dayton. Maybe that guy can check for you. You can get them with or w/o the Tbird cap on the wires.
You can get the wire hub caps that were an option in repop at CASCO and probably others. The hub caps are about 1/4 the cost of the real wires.
I have the originals with the wire clips that holds on the wire piece. They are a real PITA. The repops are easier to get on and off.
They are a PAIN to clean.