Re: Tsuki Kotegaeshi Ura??
Many schools determine omote or ura based on the direction and positions of the final movement. You might tenkan and "catch" the punch in the same manner for both versions, but omote or ura may be based on what you do from there, be it pulling uke around to the rear by his attacking arm and throwing him (ura), or by stepping back to his front and throwing him there (omote). There are numerous other variations, and perhaps your instructor prefers his own interpretation. This is why you should speak to him/her or to a senior student for the preferred way(s). Do not be afraid to ask your teacher these questions directly, as all knowledge begins with the words "I don't know".