(1) the retirement board of such retirement system, pending the final determination of a claim for workmen's compensation benefits, may authorize payment of all or any part of benefits which are payable under such rules and regulations and with respect to which benefits limitations or restrictions based on workmen's compensation benefits are applicable under such rules and regulations; and
(2) in the event that such authorization is granted by the retirement board, such retirement system shall be entitled to reimbursement out of the unpaid installment or installments of compensation due under the workmen's compensation law provided that claim therefor is filed with the workmen's compensation board, together with proof of the fact and amount of payment.