I now have some headlights. I don't know if they are correct for my '21 but they are what's going on it. They are single bulb, with the socket in the center of the backside of the bucket. The car is, of course, an electric start, generator equipped car. Are they the correct ones?
If you could post a photo, people could answer your question, not knowing anything about the headlights except that they sound like they will bolt on and that it has a single socket. There is a number of ones that will fit properly. Most of the differences in those are the ring that holds the lenses. I believe that yours should be black.
Except for the very early 1915 head lights ALL head lights used the same ring design that holds the lenses in place. From 1915 to 1925 (later with TT) any single bulb Ford head light will bolt on and work. The 2 bulb shell and reflector that was used for a short time around 1920, would still use the same ring and lens and would mount the same.
If you look close around the area where the electric plug fits the center socket assembly, you will find Ford on the top side and Brown or perhaps some other name on the bottom side.
I am restoring the headlights that I got a couple of days ago. I use the electrolysis method to remove rust. I've done it for 25 years. For the reflectors , after washing them with soap and water, I used the cleaner sold for use on stove cook-tops. It worked pretty well.I will probably need parts for the headlights, like retaining rings, sockets,adjusting screws, and one fluted lens. I have what I believe to be the correct taillight for my '21 also. It will get the same treatment. I will need the tag light lens for it.