These sign poles were made by several different companies and were purchased by oil companies and jobbers. At times, when a company wanted conformity in their advertising, they would contract with a single company to supply the poles for their signage. There were a lot of variables and combinations between these companies, and poles could differ a lot at times.
The sign hanging arm, whether singular or double, was usually a piece of pipe that went thru a sleeved opening in the pole and that arm was usually supported with some ornamental strapping to support the weight.
Lighting was usually wired thru those pipes and attached to lights that were mounted on a cross bar. I have attached pictures of a pole commonly used by Standard Oil that shows these features. This pole was also used by other companies.
