Of course, in the NTXBG (and, by extension, at NABGO, which, at present, follows the NTXBG rules by default for simplicity) unlike WWCC, carriers get the sidemount weapons, plus any secondaries (over 3"). No artificial iomitations. If you can figure out how to arm it, go on ahead and arm what you want of the prototype ship's guns over 3".
I Think you will find the NTXBG ruleset much closer to the old MBG ruleset.
But, that is just my .o2, ymmv.
Cheers,