I did not remember to take this to said friend and it's now not possible. However I came across another document today (not checked if it's the one I previously linked to ) but immediately I saw the glass and some of the writing, I thought of your becher! particularly the writing on the goblet on seite 43. So going on gut instinct, there might be something in it

The document is from Pressglas-korrespondenz - the glass is from Osredek Croatia if I can understand it correctly:
https://pressglas-korrespondenz.de/aktuelles/pdf/pk-2015-2w-vorgic-osredek-kroatien-zeittafel.pdfupdate - I've just checked and it's not the same link I provided previously. However the glass on the link I provided is I think in this document as well. So there is more than one item in PGK that reminds me of your becher.
The becher on page 9 (dated c.1900) is very similar in shape and also in the design effect somehow.
I hope I'm right

I think I am
