I'll expand. Certainly, there are elements of the Kent persona that are a fabrication (e.g., needing glasses, being clumbsy), but unlike the fakeness of Bruce Wayne (e.g., drunken playboy antics), at the end of the day, Superman looks forward to coming home and being himself as Clark Kent, whereas if Batman had his way, he would have no need for the drunken persona and spend all his time in his cave. That said, I beleive both of their true personas are a third. For Clark, it's being at home with Lois and for Bruce it's being himself in the cave without a mask with Alfred or whoever. But there is a fine line difference between the two and it comes down to Superman wishing he could be Clark all the time. He tried it when he first started saving the space plane in street clothes and it showed him that he needed some sort of disguise.
Anyways, my two cents. Have at 'em.