Hi all,I found 3 of these 7" blown glasses the other day,they are all minutely different in weight and height with striations and one or two air bubbles,there isn't a polished Pontil but I'm sure they are blown?.They all have a etched measurement mark reading 6/20L,I have no hard and fast theories although I know the Belgians are big on their beers and make individual glasses for them.Any thoughts many thanks.