ok, i will also reserve judgement on this now, but from you initial "dubious origins" post amd price paid my initial reaction was China or Hong Kong. The patchy toning is also something that has been seen recently in Chinese originated coins, most notably a Victoria florin quite recently. Sometimes a bargain can be found but i'd be surprised if this is actually one of them. Better pictures or a scan of the coin and uploaded into photobucket and the IMG url pasted into a post can hopefully help with the surface of the coin.