No matter what, there will always be a camp that says "Yes" and another says "No."
Sorta like Elvis, I think somebody saw him yesterday walking in Memphis.
Think about what could be faked today, with computers and all. All the numbers and pictures can still be suspect.
That's about where I am about now. It takes more than an R to make it a Hemi car too, and the parts in an assembly line would have to be there in late 71. Not out of the question for sure.
It could be a last 71 built, but 72 body grill and tail panel. If there was a strike at that time, a "screw you to the company" could be that car. It would be a white elephent, because it probably couldn't get insured.
Hey, I'm part of a Union. There's always a "whoz your daddy" work atmosphere.
Also if the company found out about it, it wouldn't get off the property.
More muddy if the car did make it through, if it ever wrecked beyond repair, all the parts, number, paperwork could have been transfered to a regular 72. Hence wheres the motor.
I'd love there to be one, real or not, nice mystery. The internet is a great place to start one.
Today, cars are built with the parts that are ship the same day. I work for a major Railroad and dealing with auto parts is a big business.
One train is called the Shut Down Train, if the auto parts are not at the door, the assembly line shuts down.
Then we have to pay for the day that was lost.
Car companys have no space to ware house parts at the assembly plant, they come in as needed.
Disclamer:
Just a point nothing to do with Plymouth 32 yrs ago. They might have a parts ware house, I wasn't there.