Late-war anti-aircraft armament in prewar fleets

What if prewar navies fitted anti-aircraft batteries comparable to late-war US Navy levels?

They would have more firepower available when wartime air attacks began; further consequences are left unspecified.

The counterfactual equips prewar fleets with anti-aircraft batteries comparable to late-war US Navy fits. That gives them more defensive firepower when wartime air attacks begin. Installation requirements and wider campaign effects remain unspecified.