Without verifiable documentation, this is just another V8 conversion. If I was contemplating paying 43-large for something described as "rare", "original" and "a survivor", I'd expect at least a modicum of documentation and certainly more photos showing the unique features and modifications that make this something other than a good fake. If it was converted by Scarab it's a low option version, no flares, different rear spoiler, etc.
Unfortunately, there doesn't appear to be definitive information on the differences between factory vs. self-converted cars.
Caveat emptor, friends.
And seller, if you don't like my opinion, that's your issue, not mine.