In an antique centre recently I bought a piece of cut stemware with a square top, marked on the base with the acid etched mark for Webb Corbett which was apparently used between 1930 and 1947. Then, a few days later, I saw another one on ebay so I bought that as well. However, when the second one arrived it turned out to be slightly different. It doesn't have the star-cut foot, and the number of cuts on each side in the 'arrow-head' shape are different, my first purchase having 13 lines and the second 17. The one with the plain foot is also marked with the acid etched mark used from 1930 to '47 but in the centre of the foot, whereas the star-cut foot is marked as one would expect on the edge.
Can any experts on cut glass explain the differences please? Would the design have changed during the years that particular mark was used, or is the plain footed one a mistake, or a 'second'? And does any Webb Corbett expert know what the design was called, and also what was the purpose of these items?
Thanks very much.