How useful would a greatly improved pre-war anti-aircraft battery be on an older super-dreadnought?
Short answerIt would help under frequent air attack, but its practical effect depends on the ship's deployments and exposure.
NotesThe proposed battery would make the ship more capable against aircraft, but the practical improvement depends on where and how the ship is used. A vessel repeatedly operating under air threat would gain real value from the larger fit. If its missions rarely brought it near hostile aircraft, the additional weapons would change much less about its service. Deployment determines whether the stronger armament earns its weight and crew requirements.