They must be popular. They were not available as reproduction parts until about the last 6-8 years. Now, as noted by George, almost all the reproduction parts vendors sell them. They come painted or chromed; and, 12v LED versions are available, and 6v dual-filament replacement bulbs are available.
They were an option or an accessory from 47-55.
I have a NOS set on my 1954 Suburban; and, I gave a treasured junk-yard-find (in 1974) original pair to a fellow stovebolter who is restoring a GMC suburban.
