I have a 1971 340 duster and when I acquired the car in 1990 it was all original faded paint with the duster cloud on the rear panel without the 340 callout. I thought the same thing it should say 340. I have since come to the conclusion that 71 cars didn't have the 340 on the rear . Seen quite a few without and now another. Just my observations you may disagree. Great story by the way . Can't stop reading till I'm finished. Lol.