Each such policy shall have a space for the name of the beneficiary designated with a reservation of the right to designate or change the beneficiary after the issuance of the policy. The policy may also provide that no designation or change of beneficiary shall be binding on the insurer until endorsed on the policy by the insurer and that the insurer may refuse to endorse the name of any proposed beneficiary who does not appear to the insurer to have an insurable interest in the life of the insured.