Reply to bcwayne:
The number for DuPonts Acrylic Enamel is 421A. It sprays and covers well, but its also pricey compared to Cats paints, or Rustoleum, or others.
Here are a couple of pics of a D-2 painted with the 421A.
Thanks to ypou who responded to my inquiry about highway yellow paint. I called a DuPont dealer and and was quoted a price of $145.90 per gallon for their #421A paint plus the necessary hardener plus the necessary thinner. Next I called a dealer in Ohio who had the highway yellow in stock. He told me that the shipping would be outrageous because of the hazardous materials surcharge and that it would be way more than the gas it would take to drive to my closest dealer 60 miles away. I called my dealer, Milton Cat in Batavia, NY, and they had the two gallons I needed. When I went there they assured me that the #4C4185 was the correct authentic color for the old highway yellow. Their price was $56.34 per gallon plus $16.78 for a gallon of the recommended thinner #4C4189. When I got home I stirred up a gallon and took the paint stir stick out to one of my freshly cleaned D2's and it was a perfect match. I am very happy with the whole transaction. I hope this helps the other people who need to paint their Cats, and I hope this puts to rest all the other numbers, names, and formulas that I have seen floating around. This is the real deal!
Also, the folks at Milton Cat told me that they don't always have this paint in inventory, and sometimes it must be ordered, so it would be prudent to call ahead to your Cat dealer and see if they have it in stock.