Serbia - 50 Para 1915 (a)

There a few mysteries, at least for me, to found in this World War One (WWI) era 50 Para piece. Checking KM's SCWC you'll find five different varieties listed. As best as I can determine this is KM# 24.3. That makes it a silver, with designers name, and privy marks (a, cornucopia, Paris) and coin alignment. Then there's also a KM# 24.5 with all the same attributes except the description says designers signature. Both types are listed with no values. Others varieties are shown with values indicating common strikes to much scarcer availability.