Sam,
I don't have my book here, but, as I recall they were supposed to be on the passenger's side door only and are correct for 67 GTO's (and I suspect other Pontiacs?). Most guys put them on both, which is wrong to my recollection. Then again, it has been at least 5 years since I have restored a '67.
I can't speak to the placement/ years used on Chebbies but am sure plenty of members here can chime in on that.
You're a Mopar guy, think of it as GM's version of the Mopar "crown" on the passenger's fender
Colin