You bring up a valid point, and what is not clear is the information about moulds, and licensing. I am increasingly aware of items from CZ designs, which have Italy stamped on the base. Licensed? a mould purchase? a straight copy? who knows? and I am less than confident it will be possible to find out. As you are aware, regarding the Hortensja and Rosice vase, who can say which came first, like-wise Rosice pattern number 5123, which a new pattern book discovery shows is clearly the same vase as VLG Lausitz pattern "Gent", but who produced the vase first, and when? Lausitz is definitely producing in 1969, their catalogue tells us so, and Rosice pattern number shows a date after 1965, as the number is later than transferred moulds from Nemsova, in Slovakia, but we have no way of being certain that this mould was not also a transfer from that factory, in which case it could be much earlier. Yet the pattern is clearly the same as a fruit service and plates in pattern number range 200-204, produced by Rosice in the mid-1950s.
Oh the joys of research.