if you shine a torch over the surface, you might be able to see a little wear at the right angle.
But fingernails are really very good, unless you chew them.

My Grandpa had cocktail glasses very similar to this, with the same sort of cutting on the bowl (not on the base) and the stems were amber. I thought those were Bohemian - a different colour of stem and base with a clear bowl often does, to me.