Their economy is almost bankrupt anyway. Besides, they just signed a massive deal with China to develop natural gas fields in Iran. My biggest concern would be that Iran has already purchased the components necessary on the black market to build a warhead which can effectively hedge their expectancy that the world would try to shut down their program once it became public knowledge. They had to realize this long ago - that their program for self sufficient nuclear armament would be doomed unless they could acquire a stopgap weapon to keep the world at bay.
That's what should concern us.
But if they had one wouldn't they conduct an underground "test" explosion just like North Korea did a few years ago. Kim Jong Il obviously benefited from this.