Preparing gun upgrades under treaty limits

Did naval treaties prevent ships from receiving upgraded guns?

They could restrict immediate changes, but mountings might be prepared during refits so larger barrels could be fitted rapidly once the limits ended.

Treaty rules could obstruct a straightforward increase in gun calibre, but the gun barrel differed from the mounting that would have to accept it. A navy might improve those mountings during an otherwise permitted refit without immediately installing the larger gun. Barrels could then be changed more quickly once war or treaty collapse removed the restriction. The idea resembles treaty cruisers that acquired additional armour after the legal limits ceased to matter. The proposal is a counterfactual interpretation of how preparatory engineering could shorten a later wartime conversion.