I agree with tenacious and Sap in that this coin is a fake. It looks to be from the infamous bulgarian school of forgeries. It is a good looking coin, but as tenacious said, "This obverse design style is a well known fake design. It shows up on eBay from time to time." I was almost fooled by one for sale on e-bay a few weeks ago. Sadly the other coin you mentioned minted in Amphipolis could possibly be fake if you got it from the same dealer.