Executive Orders are just orders by the President to the Executive Branch of Government. This is done by the President to make sure that LAWs are followed and enforced by the Executive Branch. Therefore, the reality of this process is that Executive Orders are NOT LAWS set into motion and actuated by Congress (the rightful creators of law) and are not enforceable. Note: “LAWs”.
So yes, if the Executive Orders set in motion by the president don’t conform to the Constitution, such Executive Orders can be challenged through the courts and thus ignored, at least until such time as the courts find them to be effectual and proper laws. Which, according to the history of the process confirmed by the Health Care debacle currently being thrust into action by the courts, and Obama’s rightful pursuit of the position he currently carries could take a while.
Meanwhile, keep your guns and use them if necessary!