Subject to the terms of the group policy relating to assignment of rights or incidents of ownership thereunder, an assignment by the insured, whether made before or after June 17, 1981, shall vest in the assignee all of such rights or incidents of ownership so assigned in accordance with any provisions of the assignment as to the effective date thereof, but the assignment shall be without prejudice to the insurer on account of any payment it may make or individual policy it may issue prior to receipt of notice of the assignment.