I believe you and I wasn't even a glimmer in Dad's eye in '68. But I also believe the factory and subsequent dealerships did some things that were never mentioned... Like a mechanic blowing up the original Hemi on the PDI test drive. I know the mechanic that got fired for it (much older than me but story was verified...lol). The owner of the new car was not told there was a warranty longblock in it from the day before they picked it up... Or the new unsold cars that got full repaints after they were backed off a carrier with the upper deck a hair too low (happened when I was working at the dealership). You can never say never with mopar (or dealerships).
Blueprint spec is just that. Unfortuntely, the factory never blueprinted anything and I've yet to see a 383 deck that was even close to blueprint spec. As Johnsaid, I've only seen about 8 of them... Not a real big representation honestly but with no exceptions and similar findings on all factory engines regardless of displacement I trust the trend......lol.