Were early 4 speeds painted?

Restoring my '65 FS 273 with 4 speed. The transmission is cleaned, rebuilt and ready to go, but can't decide if I should paint it or leave it natural. There is (what I believe to be) a factory stencil number 4 on the side, It looks like it was made over black paint, and there is evidence of black paint on the casting. Casting date 10-9. Anyone know if these were painted black at the factory, or should I just leave it be?