I would tag the books, regardless... unless you have eidetic memory or something.  here's why; if I remember right, it's a 90 minute, 75 question exam.  That gives you a smidge over 1 minute a question.  If you have to refer to your books, do you want to be frantically thumbing through pages trying to find a specific piece of information?  Next thing you know, you spent five minutes looking up a topic... 

Tagging your books is a common "open book exam" practice.  You could go without doing it, but why?  Sure it takes some time, but it also assures a better chance at passing the exam. While you're tagging, it also gives you the opportunity to review the material as well (i'm tagging and highlighting my books at the same time), which is never a bad thing.

Just my couple of pennies.

Thanks again.

I will take more seriously the tagging. It is my first open book exam.

I give myself another month until the exam, so I have time to do it the right way. After tagging I will take a practice exam to see what I am missing.

Anyway, I am pretty scared by the exam