Can't say that I've ever seen them either...
Maybe with an image search the Google algorithm could identify them?
They
are pretty distinctive.
BTW, you have a
really clean truck!
(Especially for the northern Midwest rust belt)
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.