The earliest King Fire Department lanterns were introduced about 1900 with the drop down cage. The versions with the hinged cage were introduced about 1906. Production of the King Fire lanterns supposedly ended about 1939-1940. They were offered in solid brass, nickel plated brass and copper fount with tin frames. Some of the copper fount versions were painted red enamel including the copper fount and some just the frame.
Your lantern is not plated, it is really copper, the magnet sticks to it because all versions of the King Fire lantern have a double wall fount, the inner wall is made of tin and will attract a magnet. That's so if the brass or copper cracks they won't leak. If you look inside with a flashlight you'll see the inner lining.
Red, blue and green globes were available as well as red, blue and green over clear globes like the conductors lanterns had. I think I recall seeing one that had a clear globe with a blue bulls eye lens in it but that was a long time ago and I'm not certain it was a King.