From the three examples that have been identified, it appears that all of the three coins were produced from the same obverse and reverse dies, meaning a single die produced all three examples. Without additional examples I think it may be premature to jump to any conclusions on the basis of just this observation at this time. If you are aware of other examples of this coin, please email me.
It may be that Von Post acquired this coin while he was Swedish Ambassador in Turkey from 1946-1951. Though we can only surmise through this information that the possible find spot was somewhere in that region, perhaps even Cilicia where it is possible that it was minted. Though no certain conclusions can be reached with our circumstantial evidence being stretched to such ends. Without the original information on the provenance of the coin we are left poorer and our theories on origin all the weaker.
Sotheby's Auction Catalogue 9 October 1995
Houghton etal, Seleucid Coins Part II (Vol 1 & 2)
SNG Von Post
Naville X 1925
Hoover, HGC Handbook of Syrian Coins Vol. 9
Thanks are extended to ANS Librarian David Hill who provided copies of the pertinent portions of Naville X and the Sotheby's auction catalogues.