No its not mandatory, I just passed it last Thursday.
There are a lot of practice materials on the web you can just Google around for them.
I used this book to study: www.amazon.com/.../ref=sr_1_sc_1
I also used this article: www.dynamicscrmtrickbag.com/.../preparing-for-exam-mb2-866-microsoft-dynamics-crm-2011-customization-and-configuration