hello Jonathon - welcome to the GMB
do understand what your question is asking, but perhaps the wording is a little inappropriate in relation to glass. The word vintage is really meaningless unless accompanied by a specific year - it's an expression borrowed from the world of wine - and can apply to any year, whether recent or ancient.
I appreciate that it's fashionable to describe items as being vintage or retro, and these words may have a more precise meaning in other areas of collecting, although since it's a tad on the subjective side, then it's open to some variation in definition and is thus potentially confusing. But the expression vintage has certainly gained a big following in some areas of collectibles and is obviously here to stay whether we like it or not............ so perhaps a rather broad time scale of 25 -50 years might be termed vintage.
What do other people think of this suggestion?
Sorry, can't help with an attribution for your piece of glass - I'd suggest it's quite modern in appearance and is therefore not vintage. Since you say 'these' - do we assume you have more than one??