1941-1948 Ford and Mercury club coupes- two different roofs. why the difference?

[Chris]

Hello everyone. I have noticed two different roof designs on the 1941-1948 Ford and Mercury long door coupes. My car has a droop rail that sweeps all the way to the trunk opening and has a softer transition between the back window and trunk opening. I have seen a few coupes with a drip rail that stops abruptly at a 45 degree angle and has a sharp line across the back of the roof, between the rear window and trunk lid. Does anyone know why the differences between these two? Did Mercury have the different roof over ford?