We returned several months later to the site where the Jeffery 185 was found [id=90579392] in the hopes of finding more. We didn't find much, but the very next spot on the line (to the north) yielded this insulator.

Notice the wires on the pin, just below the insulator. These wrap around the tree to help hold the pin to the tree. The nails are still in the side pin as well. Other pins we found didn't have insulators, but they also were tied to the tree like this one.

I originally thought this was a 162.1. After consultation with Lee Brewer, sharing other photos of the same insulator, we have decided this is a 162.3.