As I recall the large number of different mods of the 5" Mark 30 mount are because of interlocks for the positions these guns could be mounted on DDs and other ships. I understand this to be the reason there are so many different mods that look visibly identical in photos (and indeed have almost carbon copy Gun Mount and Turret Catalog entries).
I am loving this thread and the clear attention to detail on this model!
One suggestion -- USN hull numbers used a specific face and Helvetica is not a good match.
You can see the squared off/stenciled hull numbers in this low-res photo of RANDALL.
This BuShips drawing shows the numerals as specified in 1937 with 96" hull numbers for DDs. Obviously during wartime the numbers were smaller (24" on most ships) and unshaded - though I'm personally not sure of the exact painting guide/dimensions for the APAs. The numbers on the photo of RANDALL are clearly taller than 24"!
Two font faces I've found that roughly approximate the numerals above are "USN Stencil" and "USAAF Stencil". Note that neither is a perfect match. Also, the RANDALL photo shows the lower left corner of the "4" with a 45 degree angle to it when the USN design sheet above shows a 90 degree angle at that position. Researchers more knowledgeable than I would need to comment on why there would be a difference -- my guess is that yards painted these numbers and had a certain degree of freedom in their exact application, or the numbers were painted at a forward base by the crew but obviously this is speculation.
Here are download links for the two fonts described above (they are free):
https://www.dafont.com/usn-stencil.fonthttps://www.dafont.com/usaaf-stencil.fontI hope this helps! Your work on this ship is so exacting and accurate and I've really enjoyed watching the progress in this thread!