Raja,
Yes. Exactly!
The Exam Content Outline (ECO) defines what you will be tested on during your CAPM exam. Therefore, if the learning goals states that you have to be able to "identify purpose and elements of a WBS", then you have to expect that your exam COULD have a question about this topic.
My tip: Print out the ECO and take highlighters (green, yellow, red) and then highlight each learning goal. Green for "I know this well", yellow for "I've heard of this" and red for "No idea what they are talking about". Now you can identify your weak areas and you can study with a better focus.