Trustee May Demand Production of Notes. The Trustee shall have the right to demand production of the Notes of any series in respect of which any payment of principal, interest or premium (if any) required by this Article 7 is made and may cause to be endorsed on the same a memorandum of the amount so paid and the date of payment, but the Trustee may, in its discretion, dispense with such production and endorsement, upon such indemnity being given to it and to the Issuer as the Trustee shall deem sufficient.