I would bet that a truck ordered with a non-standard color would most likely have a beltline pinstripe.

I know that the pinstripe was not put on all "standard color" A-D trucks but I also know that standard color trucks might have had the pinstripe. (how's that for a complex sentence?)

I realize that there was really no "standard" color each year - all colors were available as a no-cost option. However, there was common color for each year - might as well call it standard.