When working on old trucks who knows what's swapped out. I've bought a few turn signal cams over the years from various sources. The majority of the turn signals and cams have come from Shee-Mar Inc here's the link

http://www.shee-mar.com/parts.html

This company has been around for years. IIRC the first cam I bought was in the early 70s for a 60 panel, maybe that was a switch. They mucked with their catalog and I had a hard time finding the early truck parts. They are there including illustrations and pictures.

Larry

I don't own a vehicle that isn't old enough to drink.