You provided the correct info Delorean, so the point goes to you.
A Vignale web site indicates that they built 3 prototypes for Tatra. One was crash-tested, the other two survived.
I just read a poorly-translated web page about the creation of a T613 coupe replica. It seems Tatra created a red replica coupe in 1977, and 6 or 7 others have been built by individuals.