Here's another oneversion of the history of the cup. Made in Romania in 1938 (?). Manufacturer "FB". Silver fineness 750 (round mark). In modern times, it is "ennobled" with a fake Russian punch.
Arguments: maker's mark "FB", number as on Romanian items, fineness 750 ( in Romania 84 zolotniks silver would be put a fineness 800). And, finally, the clumsy Russian hallmarks.