Yes, absolutely.
Right now, there is NOTHING in the exam that is not part of the specification. That will probably change with future versions of the exam, but not for the beta or this first final release of the exam.
Most of us *do* recommend using another book to learn from, however, unless you already know and understand EJBs well.
My advice to all would be:
1) If you know EJB well, study the spec, using the objectives. Be sure that you do not just memorize the facts, but that you also *know* the implications. Know what it *means* to remove a bean, for example, not just *how* you do it.
2) If you come across just a few small things in the spec that you don't understand, then you might want to go to your local bookstore and just browse a few pages to see if that clears it up, before having to commit to buying a book.
3) If you do NOT know EJB really well, or you find that you do not understand many parts of the spec (remember, the spec was not meant to be a 'learning' document), buy or borrow a book. Most of us here recommend either the O'Reilly book or the Ed Roman book.
4) In early September, when the final exam is released, there is a rumour that a new study guide for this exam will be out, which will also be a learning book for the topics. So if you don't know EJB really really well, or you just want a feel for what the exam is like, or you just want to help support two starving writers (me and Bert

), then you might want to get that book when it comes out. Won't help you for the beta, however.
Have fun
-Kathy