My Question: What does W. O. C. O. stand for?
Looking through a box of auction treasures, I found this rather dirty tail light and put it in my ultrasonic cleaner to clean it up, but the ammonia took all the paint off.
W. O. CO. TYPE-A is stamped in the top.
The two 1/4 inch studs are 1 1/2 inch apart and fit the 1926 mounting bracket, but only if the bulb connection is on top.
There is a clear glass cup insert inside that looks just like the 1926 glass cup insert, without the circle pattern, but is about 1/8 inch shorter.
That is covered by a red glass lens that has a Z at the top and JEFFERSON 926 around the inside bottom edge.
There is a standard notch cut in the bottom metal case to illuminate a license plate.
The bulb socket has a single contact area.
I have seen the Type A designation on other lamps of that type. Willys Overland came to mind but just a guess.