I just bought a 1930's Phillip 66 gas station in Blackwell Oklahoma, this could be one of the first 10 or 12 built.
On the exterior of the fireplace and the end of the building near the peak are 2 openings that had a glass face about 14 1/2" in diameter with the orange and black Phillips 66. I have the steel rings and brass screws one glass was completely gone and the other doesn't have enough pieces to make it repairable