Personally, I don't think it is necessary, but it should depend on how you feel about EA after taking sample questions. The positive side of EA is that it is designed to test your immediate knowledge (without much prep) instead of hours of preparation for GMAT with memorization and geometry. It is definitely more tailored to EMBA students.
Have you taken practice questions? If so, where you are on them?
Give an example, I used one weekend to prepare for EA and got 160 in the coming week. Practice questions are very similar to the real test while I felt real test is little more difficult, as I was doing a lot better in the practice questions especially in IR and Verbal sections.
I plan to write a short article to go over how I prepared when I get time in coming weeks. The biggest challenge to me and many other people is the time management, especially in IR and Verbal for me.