Yes, it’s yellow paper. No it hasn’t yellowed over the years. It was yellow form the start, from a large box of foolscap-sized paper by Dad bought for 5 shillings (25p/35¢) from British Rail some 6 or 7 years previous.
Please note gratuitous introduction of Emerson, Lake & Palmer… plus a ludicrous remark commenting that Man were “the most promising name in rock today”. To coin a phrase… LOL!!