N & B Mini-Miura Nimbus Studio GT 2-litri

A story on the cars here

http://www.**************/cars/3082.html



From the back this one off (acutally two off) speciale looks like a baby Lamborghini Miura.
They were not sponsored by any automaker, more just sprung out of a private body shop ( N & B) I was just wondering if any of the two was bought at a reasonable price back when things were reasonable and what they have done lately at auctions.? By theory is that, by having no automaker behind their construction, they are "without portfolio," customs but at least customs done in period in Italy. Or does age add a certain patina? Opinions?