thanks for the explanation

I agree with you that when in doubt, buy ......... nothing worse that inconsolable regret for things we didn't do - I've been there ............ that's of course assuming the price isn't through the roof.

To be accurate regarding the possibility of u. you would need a u.v torch - without it we can sometimes pass over a piece - especially opaque type glass like this - and not realize it's there - Sowerby's Patent Queen's Ivory Ware is a good example of that pitfall.
Age can be deceptive in appearance on glass - utility wares will usually show more than a decorative item that may have sat in someone's display cabinet for many decades. Regret I'm fresh out of suggestions, so will leave to others to try and help - very best of luck, and thanks for posting.