All of the Iowas had some differences from each other. Iowa and Wisconsin, for instance, retained their 20mm bow tubs, while New Jersey and Missouri lost theirs during their Korea-era reactivation.
For a 1980's Missouri made using one of the two 1/350 Iowa-class kits (Tamiya New Jersey and Revell, which was boxed as both the New Jersey and the Iowa), the biggest difference is going to be the fairing that Iowa, Missouri and Wisconsin had at the top of their forward ECM/FCD stack. New Jersey didn't have the fairing, and the forward top of ECM/FCD stack was braced using H-shaped tubing. The Revell kit of the Iowa had a piece for the fairing, but it was a VERY poor fit that didn't represent anything near what the fairing looked like.
Secondary differences for Gulf War Missouri include antennas, for instance there was a ball-shaped dome mounted on the front side of the rear exhaust stake. Also the Pioneer UAV apparatus on the fantail, which involved a cutting down of one of the old 40mm tubs and installation of a fuel bladder.
Those are the ones that would require some scratch-building. There were also ship-specific differences in the non-skid applied to the fantail area extending up to the rear deckhouse.
