All warships have voids between the inner and outer hulls  , as do all " double hull " merchant vessels .

I've been into many of the voids , too many , on the Theodore Roosevelt to do inspections with shipyard personnel after we completed shock trials .

The fact that I now see that only the last couple of feet of the hull isn't represented reinforces the supposition that Revell produced the model that way to sit nicely on a shelf . ..   It's really weird having that much hull and no screws .

I don't know why they did it that way but it can't be the lack of info available at the time .

https://www.modellversium.de/galerie/5-schiffe-ww2/14293-uss-missouri-revell.html