Yes Mark, signed Vizner's piece are rare and all of them are new, even designs are old and "re-freshed". The limited collection was ordered by Alchymie (up to 3-4 hunderds) but when fabricated, contract had been terminated and some pieces sustained in factory. I am lucky buyer of few of them.
Mark, can you please tell me, display or post the overal picture of signed Beranek piece? Meanwhile I was checking Skrdlovice Symposias, seems to me that in 1979 had not been performed. But still exist chance to find the true, Jan BerĂˇnek or his son Vlastimil could help.