It would be interesting and useful to determine exact composition of the alloy.
Fortunately, there are electronic testers now.
Why is alloy composition important ?
1.Silver contents can be compared with standards used in various countries and narrow the search.
2.Old silver alloys are well known to have several trace metals (e.g. gold) beside copper being the principal alloying metal. Those ``impurities`` in old silver are the result of imperfect metallurgical methods at the time.
Two more references for Győr (Raab) mark; it is really a distinctive cross.

Győr (Raab) is above letter
e.
Regards