Am not a streetlight expert, but I spotted this image online. It's a frame grab from the movie "Silver Streak" (1976). That's the late Gene Wilder in the shotgun seat of a 1946 Mercury Eight Town Sedan. Check out the light fixture in the background, however.

As for the two insulators at the top, the farm scene was filmed in the Mojave Desert of California, so the insulators could be straw CD 106 McLaughlins or Maydwells, if not clear CD 106 Hemingrays.

Joe Maurath provided an update: The outdoor light fixture in the photo is more of the type that was used along railroad station waiting areas, on the sides of barns and for commercial use on privately-owned buildings, etc. These were lower-wattage lights and not of the heavy-duty type. Utilities and communities favored larger fixtures with beefier brackets for long service life and for accommodating larger light bulbs, notably from around 1920-onwards.

Thanks, Joe.