We are talking about gold coins here, and fake gold coins. Not easy.
It depends. It would be very hard to fool a jeweler, but a gold colored coin is enough to disrupt a lot of transactions. You can easily electroplate a copper coin with a little zinc then heat treat it and turn it gold (brass really).
Ideas are not censored here. Supplying IS with bitcoin or buying one of their coins is material support. Talking about their plans to make coins is not.