So many things about this car that aren't "factory". I bought it 27 years ago (hey, life happened...so here I am restoring it in my old age). It had all the GTS badges on it, and it was a 340, 4 spd car, so I jumped on it for $4,500.
The VIN on the dash matches the engine, matches the transmission.
The numbers on the trunk lip and on the core support match.
HOWEVER:
There was a fender tag on it, but I knew nothing about what all that meant. Turns out, it was fender tag from a random charger.
It had to have been a 4 spd swap, because the fender-side ball stud for the z-bar was mounted in a hole cut into the sheet metal of the inner fender...nothing else. Of course, the sheet metal was ripped out.
I guess a previous owner did a fairly decent job otherwise of swapping things...such as changing out the upper steering column housings to eliminate the AT gear-shift. When I took the column apart recently, I found remnants of the AT gear-shift tube and spring.
The rear leaf spring mounts were the wrong (i.e. smaller) diameter bolts; not meant for a GTS.
There were no torque boxes
When I stripped the vinyl top and paint off the car, I found large leaded body filler joints in the rear pillars. (Factory????)
Of course, most of this could have been a case of Ma Mopar sending something off the line with whatever parts were available so to not slow down the line. But still, I will never surreptitiously try to pawn this car off as an honest-to-goodness 1968 Dodge Dart GTS, 340 4-Spd.