Normally I'd advise against making the assumption that a plastic kit is exactly as long as it should be. Various manufacturers have made some pretty big mistakes in that department. In this particular case, though, on the basis of having measured the kit (before I read Sumpter's post), I can report that Trumpeter got it right.
The North Carolina's overall length is identical to the length of the hull, there being no overhanging parts. So (unless you build the model with the aircraft crane swung around aft) the length of the above-water hull part will be the length of the finished model. The hull of the Trumpeter 1/700- scale kit measures 12 31/64", or (according to my calculator) 12.485375", long. For me, at least, that's close enough to 12.48".
Some of Trumpeter's ship kits have taken some rather harsh criticism, but I have to say, as a fan (and semi-near neighbor) of the North Carolina, that I really like this one. It has the potential to be turned into a beautiful model - especially if it gets a little help from an aftermarket detail set (such as the excellent one offered by Gold Medal Models). All due credit to Trumpeter.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.