Most Style 4 Baby Ben bases are painted gold on the bottom. Starting in 1937, some are painted the same as the case. Gold bottom bases have a brass nut in the center. Ivory and Gunmetal bottom bases have a nickel nut in the center. Some of the Ivory and Gunmetal bottom bases have a plated outside edge (like the gold bottom bases), others are unplated.
Base Bottom Color Gold:
Gold painted bottom.
Base Bottom Color Matching Unplated:
Base bottom is Ivory or Gunmetal, and the outside edge is not plated.
Base Bottom Color Matching Plated:
Base bottom is Ivory or Gunmetal, and the outside edge is plated.
