if 2 of them are aft on the quarterdeck near no. 3 turret and the other 2 are on the boat deck just forward of the bridge structure, they are for quad 1.1" aa guns which were not installed at the time of pearl harbor. not sure how much work other than the shield was done, ie. ammo racks on the inside of the shield, electrical hookups. earlier, i believe 1937, the 2 forward tubs had 5"/51 surface guns like the ones in the casemates.
aft inboard of the gun tubs on either side is a large deck plate. on the model is this planked, as it should be, or is it shown as a metal plate?