Hi Chloe,
Not easy to tell, I know the Czech factory items came in two qualities, one, very low, with unfinished bases, and one very high quality, with mirror-polished grinding of the base.
No apology is ever necessary, our knowledge advances, and we all work together. What new information comes from Czechoslovakia, increases our comprehension of the contemporary political and social factors which will lead to a better understanding of developments in both UK and Czech glassmaking history.
Regards,
Marcus