It wouldn't surprise me if it's 1950-60s vintage. Mine's dirty but doesn't have much wear on it. I picked it up for 50p at a jumble sale last year, so £50 for one is pretty expensive.
I remember my parents buying a brand new pressed glass kerosene lamp when we were on holiday back in the 70s, although I can't remember the design on it now, but it was probably a copy of an old Victorian one. I think they were coming over from Eastern Europe at the time.