Were they?
War Department
Washington, D.C.
Major Anderson,
First Artillery, Commanding Fort Moultrie, S.C.:
Sir:
In the verbal instructions communicated to you by Major Buell you are directed to hold posession of the forts in the harbor of Charleston, and, if attacked, to defend yourself to the last extremity. Under these instructions, you might infer that you are required to make a vain and useless sacrifice of your life and the lives of the men under your command, upon a mere point of honor. This is far from the President's intentions. You are to exercise a sound military discretion on this subject.
It is neither expected nor desired that you should expose your own life and that of your men in a hopeless conflict in the defense of these forts. If they are invested or attacked by a force so superior that resistence would, in your judgement, be a useless waste of life, it will be your duty to yield to necessity and make the best terms in your power.
This will be the conduct of an honorable, brave, and humane officer, and you will be fully justified in such action. These orders are strictly confidential, and not to be communicated even to the officers under your command, without close necessity.
Very respectfully,
John B. Floyd
So where exactly are Buell's instructions countermanded?
Buchanan via Floyd to Anderson: "It is neither expected nor desired that you should expose your own life and that of your men in a hopeless conflict in the defense of these forts. If they are invested or attacked by a force so superior that resistance would, in your judgment, be a useless waste of life, it will be your duty to yield to necessity and make the best terms in your power."
Moving to Sumter did result in a hopeless conflict to defend the fort, a violation of Buchanan's instructions. Anderson apparently could only see his little piece of the situation (defending Fort Moultrie from an attack or mob that never came) and did not consider the larger political picture of war versus peace. The move to Sumter, aside from making the South Carolinians and Buchanan hopping mad, put Anderson's troops into a fort that his military superior, Winfield Scott, later said would take an invading Union force of ~25,000 men (I don't remember the exact figure) to rescue Anderson. Anderson had put his forces in a hopeless, almost indefensible situation and pushed the country closer to war.
As Buchanan said in my quote above, Anderson's move was "against my orders." I'll take Buchanan's word for it.