Almost all air meters left the factory red. Air-Scale was one exception, they were painted pumple.
If you are talking about ECOs, most were sold one at a time through local equipment warehouses. If you wanted a air meter, you called your local warehouse, the salesman came out with one in a box, it was painted red.
If you were Marathon or Mobil Oil Co. and you wanted to purchase 100-200 units for all your stations in a certain area, you usually contactd the Bennett Pump Co. directly. Their first question was usually "What color do you want them." Marathon and Mobil used white ECO meters. I have no information of any other company using a color other than red and white.+
Air meters were one of the most abused pieces of equipment in a service station. The SS operator was already mad that he had to buy a piece of equipment to give something away, and then they abused it. I would venture that very few operators took much care with the meter. Since they were usually abused, they usually needed painting more often than other equipment. That 12 year old kid that hung around the station in the 1950s and 1960s (he ownes the station now) was usually give the task of painting everything he could reach. This is how air meters became battleship gray, green, or just about any color you could imagine.
I sell air meters that have been two toned, such as blue and yellow for Sunoco. This is strictly fantacy, but it makes them sell better.
My suggestion is to have fun with your meter, paint it to match the gas pump you may have already restored, they would look great together.
If you need any air meter parts, see my website:
www.crspub.com I am presently working on a air meter book, it will identify about 450 air meters made since 1897.
Jack Sim