Hmmm, this is an Oct or later box (I only have the box, not the car it came from!) and the Sept noted is wide clips.... odd.....
Would there have been multiple manufacturers of the boxes, maybe plant specific for a change over? Or would they be similar to convertible tops, which I beleive all came from a single source and assembled in Utica and shipped to the plants...?
I am pretty sure 68's used the wider, flatter ones. All 4 of my 68's have mostly those style. And think the higher wide one is a service replacement or repro.