Glass beads sold as old, by seller in Sliven
http://www.ebay.com/itm/171282558828
The glass industry of the People's Republic of Bulgaria
Looks like they did fancy stuff before 1944 and are doing fancy stuff again. In 1944 the market was messed up. Marbles still seem too crude for what is discussed here but there still would have been a need for beads, and where there are beads, why not marbles?