If a tracker was a prerequisite at the policy's commencement, they should have informed you and would likely have requested verification. If a requirement is absent and the checkbox indicating its presence is marked, resulting in a policy discount, the insurance company will then demand evidence of its installation if the vehicle is stolen. If evidence could not be provided, they would undoubtedly reject the assertion.
Based on your statements, the conditions indicate that the claim would be denied if your vehicle lacks an operational security or tracking system; so, the interpretation of "security device" will be crucial.