No, "Out Of Bounds At All Times And No Exceptions" is not an allegory to talk about the father's absolute power.  However, I find your question to be quite ironic because I think you used the word "father's" instead of "Führer's."  In fact, both Bruno's father and the Führer have "absolute power": Bruno's father has power in the home and the Führer (Hitler) has power in Germany and Europe.  

The problem with your question is about the word "allegory."  An allegory is a story that has a hidden meaning.  A phrase would never be described as a full allegory; however, "Out Of Bounds At All Times And No Exceptions" is the title of Chapter Five and the evidence that the Nazi commandant wants his son to have nothing to do with the prisoners at Auschwitz.  

Originally, "Out Of Bounds At All Times And No Exceptions" really has to do with Bruno's father's office:

Father returned to his office which was Out Of Bounds At All Times And No Exceptions.

But instead of an allegory, I would say this phrase is a description (or even a euphemism) of Auschwitz for a "superior" German boy.  A euphemism is a mild expression meant to replace a harsh one.  Bruno's dad's office is the place where many executions are planned mercilessly.  Auschwitz is the place where may executions are carried out.  This place of horror is most certainly off limits to a German boy who needs to be protected.