Akragas on Sale - Where's it Really From?

The round piece of metal pictured here was sold by a dealer with a lot of eastern European antiques, based in Rechnitz, Austria.  The piece of metal with the pretty pictures was the subject of some vigorous bidding today on an internet auction portal near you. The bidders' identities are doubly-protected as it was a private listing, but the 38th bidder won his prize  for $555. He is sure it is a tetradrachm of Akragas, 470-420 BC. One wonders at what stage someone will be regretting that they bought something from a stranger who offered no proper information where it came from...  Collectors, forget what the dealers tell you, provenance IS important.