The light in the JC article is a Guide B-31, they were used on almost every GM division at one time or another. There were also versions for Harley-Davidson and Indian products. You will find a variety of lenses, housing mounts and chrome or painted bodies. As an example this very rare 1948 Panel Truck compartment light accessory with the, painted body, diffused lens rather than the common back-up light with clear focused lens.
https://www.flickr.com/photos/advance-design_parts_co/13957534323/in/album-72157631868452754/Novak is based out of Logan, Utah. I have sold them several SM420 cores over the years. They enjoy a stellar reputation in the off-road community. They have an excellent knowledge gateway on many transmissions located here.
https://www.novak-adapt.com/knowledge/transmission_gateway.htm
