Is it enough to read J2EE 1.4 version of this book?
Yes you can do that. There are not so many differences between EE1.4 and EE5 when it comes to the OCWCD exam. However there were many updates to the book in the second edition that you are missing now if you are having the first edition. So it is up to you to decide.
Just for curiosity: why aren't you taking the new EE6 exam?
Joined: Jul 23, 2012
I think there is no "Certified Professional" exam is there in J2EE 6, only "Expert" exam is there. That is why I preferred this.