The kit I built didn't have screws but just a rutter and the hull lacked an apparent armor belt but the Iowa's did have armor belts and a while they weren't true blisters they did have void spaces, I know this for two reason one I've seen inside that void space volunteering on a museum ship,  and two there's a good YouTube channel for the Battle Ship New Jersey in which the historian and curator goes over the ship and the rest of the Iowas in great detail.

Idk the reason for the kit missing the lower half but wether or not the reasoning was secrecy or lack of effort  is both interesting to me