Unusual installation of an upside-down insulator pin...

In other instances a "Brown's" pony insulator was designed for adding additional space for more crossarm-mounted wires. These required a special pin. The upper section was as usual with a longer continuation to its underside to accomodate another insulator. The "Brown's" insulators were open at both threaded openings so that moisture would pass through, thus promoting less likelikood of the wood pin swelling and seizing the insulator onto its wooden threads. Regular insulators were used on the upper section.

Perhaps this had the duplex pin and the top section broke off?