The measurement is for length over all (from the farthest point of the bow to the farthest point of the stern) not including the overhang of the 40mm tubs aft (which do not count as structure). At 15.19" that is dead on for 1:426, and the Currituck / Pine Island's length over all of 540'5" (compared to 527'4" for the earlier Curtiss / Ablemarle).
I have some spare stacks from an old 1:500 Renwal North Carolina that can be cut down and reshaped for the Curtiss. Looking at pictures taken after the Pearl Harbor attack, I'm going to have to scratch build the rolling hangar doors (two on either side of the centerline). The Curtiss also had a searchlight tower aft of the bridge that was modified to carry a CXAM radar set and will have to scratch build that also.
Still looking for information regarding the Curtiss's AA armament fit in Dec., 1941, but thinking that it could not have been more two 1.1" quads and some .5 mg single mounts.
Here's a photo of the Curtis in 1940 from history.navy.mil/photos - note she had three (!) cranes. Only the foremost 5" mount is enclosed and there are no 1.1" mounts in sight.
Good luck with your builds!
Mike