I was thinking half way through 2 door conversion.
Never seen or heard of it, logical if there is only one, ever made, kind of different...
If I were a betting man...I'd say it was fabricated recently.
I do remember three door Chevy Suburbans and International Travel-alls (longer version of the scout) back in the early 70s. I always thought they were odd.
What would be the use of this other than it is easier to get in the back seat on one side. Wonder if they are one of many of mopar screwups back in the day with 1 ot cars.