This is a very dangerous fake, because it has a lot of characteristics of a genuine coin. It was established to be a Balkan production, probably in early 1990. There is a multitude of those on the market and sometimes sold by reputable sellers, which helps them appear even more real.
The coin characterics are:
Obv
- number "1" misses the right top seriff
- the king's nose is differemnt than any other effigy of Sig III
Rev
- right lion's head doesnt have a lower jaw and looks like a "allien helmet"
- there are three or (rarely) four dots located below the coat of arms, in vicinity of lions' paws, which dots do not appear on the genuine coins.
Hope it helps