Czechoslovakian pressed glass post-war, a couple of recent observations.
When a design is known to have been made at a particular glassworks, it is not safe to assume all pieces in that pattern were made at that factory.
An example. A pattern by Milos Filip was put into production at Sklo Union's Rosice glass-works as vase #602. I have documentary evidence showing that the matching glass candle-stick (#2058/5) and ashtray (#2045) were produced at the Nemsova glassworks.
This may have been for one of two reasons. The first, simply that there was not sufficient spare capacity to make the complete range at one factory. The second, that the pattern was trialed at Skrdlovice, and then transferred, as a pressed glass design, and shared between the two factories, a situation not uncommon there.
The second observation is that often a contemporary source rarely gives the whole picture. Raban for example clearly states that a pressed glass container came from Rudolfova Hut in one colourway, a clear non-lead crystal base with green lid. Yet the same pattern, by Josef Soukup, number 13093, which was introduced in 1960, was offered in the reverse colourway in 1964.
The difficulties experienced due to centralised planning and control of the economy often meant shortages of materials, and thus simply because a source states "available in six colours", it is not necessarily the case that examples can be found in those colours.