The two 'flavors' of 5"/38 single gunhouses on the typical war-time Fletcher were often termed 'single knuckle' and 'double knuckle'. The single knuckle mounts had only one bend in the gunhouse roof, and lacked a gun captain's hood. These were mounts identified as 51, 53, and 55. They were located below a superfiring gun and provided better blast protection. Double knuckle mounts had two bends in the gunhouse roof and had a mount captain's hood. These were the superfiring guns at mounts 52 and 54. Good cement technique with the correct sides for the proper gunhouse core minimizes seams (use CA). The barrel should also be located off-center to the left of the mount centerline. I think Tamiya got that right, but Trumpeter missed it.
Of course there are better aftermarket options; Black Cat, Model Monkey, and L'Arsenal.
Plans are afoot to kit-mingle the Tamiya and Trumpeter offerings to make an as-launched USS Kidd with 20mms in place of the twin 40s on the deck forward of the bridge, remove the CIC extension on the bridge face, and add a square 20mm tub to the forward of the bridge deck.
To an earlier post that there was round-bridge inside of a square-bridge??? As war production efforts grew, shipyards learned that rolling steel plate to make round structures took more time and effort (read as $$) than welding flat plate to make an angular structure. Initially the equipment & locations within the square-bridge may have been similar to that in a round-bridge. That soon evolved with wartime equipment changes.
And the picture of the bow with Roman numeral depth marks. That is non standard for US practices. The US uses Arabic numerals, the size and font of which is identified in the detailed construction drawings. They are surface welded to the hull, over painted in wartime camouflage or picked-out in contrasting color in peacetime paint. The name is handled similarlt