US cruisers and destroyers become British classes

What if all US cruisers became County-class and all destroyers became Tribal-class on 1 January 1942?

Some County-class ships could offer an additional antiaircraft option, but the US Navy would probably rush to reinstall 5-inch/38 mountings.

An overnight change to County-class cruisers and Tribal-class destroyers would deprive the US Navy of familiar American weapon mountings. A suitably equipped County subclass could add an antiaircraft role for its 8-inch guns. The British 4.5-inch and 4.7-inch guns are judged good weapons, but the 5-inch/38's mounting gives the American system its exceptional dual-purpose utility. Applying comparable mounting technology to the British guns could give them a similar reputation. American ships would probably undergo rapid rearmament with 5-inch/38s to recover that capability.