Instrument Cluster Bezel 69 Dart?

Hey guys,
Today I am reassembling my instrument cluster to my repo bezel and I saw something on my original bezel that I had not seen before. Im not the original owner of this car, so I'm not sure if it was added or came oem. The inside of the cluster bezel has what appears to be white paint brushed on the back side of the bezel in each location of the gauges. It kinda sorta looks like it may help to lighten up the gauges when the lights are on. Any ideas?