I agree. Saddam tried to bluff his way out of war by hinting at his WMDs and it failed. Pakistan has tested them. Libya figured out it would lose the race and quit.
In my view, N. Korea is not bluffing. She will have nukes if the current regime continues in N. Korea. She may pretend that she is further along than she actually is, in order to gain some advantage at the negotiation table. Or she may pretend that she stopped working on nukes for the same reason. However, either way, she will get them eventually.