Yes, you must verify your dependents. In fact, there can be serious consequences, including losing coverage for yourself and your dependents, if you try to cover individuals who don't meet the definition of an eligible dependent.

You must submit your documentation within 30 days of the dependents' eligibility (your hire date or the life event date for your dependent). If valid documentation is not received, your dependent(s) will be processed as invalid and the pended dependent coverage will be removed.