ive seen a few, not many, '56s where the side trim on the front door is shortened, where the spear doesnt go almost all the way to the front of the car. They also have a secondary piece of trim on the back and is usually filled in with white. I cant seem find any info on what the difference is on these and the rest of the customlines out there. heres a pic of a wagon, but ive seen a couple pics of cars with the same trim. I really like the look and considering doing it to mine.
That is a mainline and the trim that goes all the way to the front is a custom line. The trim that you are talking about on the mainline that fills in and makes the two tone section is or was an option from the dealer or factory.
Some of the mainline had no side chrome at all. Also some came with chrome around the windshield and back lite, and some with nada.