If you search the web for photos of Robert T. Smith who was an ace with the AVG Flying Tigers and 1st Air Commando pilot, you will find a few sources of his color images from WW2. I have a couple of images that I found that show the red markings still in use in 1944. I know that akg-images has high quality prints for listed for sale on their website. There is a color photo of six aircraft in flight with the third ship from the top showing red outlines (tail number 14) and another of the same aircraft parked next to "Miss Virginia".
Hope this helps.