Our family shop sold and serviced those things back in the early 1950's, and they had absolutely nothing to do with unleaded gas. The only thing that burned unleaded in those days was a Coleman camp stove or lantern. During the Korean war, the gasoline sold on the civilian market was prone to cause massive carbon deposits due to most of the good additives being used for aviation gasoline. The upper cylinder oilers were used to inject "tune-up oil", usually Bardahl, Marvel, or Aviex, to reduce carbon deposits on intake valve stems and guides. By about 1955 or so, the gas quality improved, and the oilers became unnecessary. The only reason to run one now would be for the "old school" nostalgia of having a 1950's accessory under the hood, sort of like a traffic light prism on the dash, or a necker's knob on the steering wheel!
Jerry
