I'd say it's yer standard 3rd party fender mount turn signal, found on many trucks from the late 30's to the early 50's

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics