Just based on my experience, it's almost always impossible to explain to people why I put a larger dollar value on a car like a Z432 vs, say, a stock 1970 Z, or even a modified Z with a Rubello engine. The difference between these examples happens to matter to me, but I acknowledge I'm in the super-minority.
I can confirm the same arguments are heard across Marques. There are plenty of enthusiasts with a 1973 Porsche 911 who wonder why their car is only worth $50,000, while the guy with the 1973 RS can sell his for $1,000,000. Or why the guy with the 1960 Ferrari 250 PF II cabriolet sells his car for $2 million, while the guy with the 250 LWB California - nearly the exact same car, save for a few body panels- gets $14 million for his.
The nerdy answer fundamentally is that there are enough marque fanatics who are students of the differences, and a select few more that have the means to insist on buying only the top-end specifications, thus creating a market spread. In the case of the Z432, there are perhaps less than 200 surviving examples to choose from, in various states of originality, so when one comes up, you either buy it, or wait (potentially a long while) for the next one.