As a former detailer (and former plebe before that), I'd say the "study or not to study" decision depends on two things: (1) is it a way for you to manage your stress before you go, or are you just doing it thinking you'll have an easier ride or stand out or because you think you have to?; and (2) how you would handle your "advance knowledge" once you're in Bancroft as a plebe?
Let's start with (1). I wasn't too nervous about USNA before plebe summer -- I had a few healthy butterflies but I knew I was in good physical shape and I was from a big strict Irish Catholic family and was used to getting yelled at! (Sorry mom) One of my roommates, however, was really stressed out -- terrified on I-Day so much that he almost quit just out of nerves before he chilled out. (He did chill out, eventually, and did great at USNA.) In his nervous stage, he was prone to clutching a little bit and having everything he memorized magically fly out of his head. Had he "studied up" in reef points a little it might have given him a little bit more comfort that he'd be able to take what was going to be thrown at him with less risk that he might have quit before discovering he could hack it.
Let's move to (2). As a detailer we had a glib son-of-a-gun in our Company who had quite clearly memorized Reef Points cover to cover and wanted everybody to know it. Target was identified and neutralized quickly. (Nothing too bad, just making it clear to Mr. Big that he wasn't . . . at all. We enjoyed making the laddie memorize some interesting supplemental information.
He'll probably be Chairman of the Joint Chiefs someday -- dude was pretty smart once he stopped trying to prove it to everyone.) Don't be That Guy. However, if you keep your "advantage" to yourself and help your roommates and squadmates and company-mates out, it doesn't have to make you a target.
So, think about those two questions. In the meantime, go out and enjoy senior year (responsibly) already!