When i get a new cab for my rig, it'll either have them, or get the panel welded in. I too love them.
Too much stuff, the ones you describe have been considered (at least by the books) a correct replacement for the 69/70 hockey puck style. So the one you had had probably had them all replaced just to match after one broke.
The ones in the background in this pic, these are the correct ones for the 69/70 trucks.
