Wrong Paint from Factory ?

Hi - new here - about to purchase my first classic - 1970 Duster - the seller told me the paint colour originally ordered was Y6, however car arrived FJ6 from factory. Fender tag stamped Y6. Is there anyway / any where to confirm this story. We've been told (not by seller) that although rare - this did happen from time to time. Story continued that dealership then painted it to Y6 for customer. Next owner painted it back to FJ6. Were just trying to find as much history as possible.