That is a question that can't be answered with a clear cut answer.
The transition to the "Neutral Grays" wasn't clearcut from the older paints to the new paints by a day or even month. The USN was still trying to get the new paints into production in (a late January 1945 memo sent out the formulas for the new paints) February 1945. The USN paint makers started, but getting the private paint suppliers going took time. Hence supplies of the new paints were limited. The switch from the dazzle schemes back to Ms 21 and Ms 22 (and adding a "new" Ms 12) happened in late 1944, roughly starting in October 1944. So you can see that there were ships painted in these schemes with both types of paint. To make it further confusing, initial directions for Ms 22 said to use the older 5-N paint and the newer Haze Gray paint.
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http://www.researcheratlarge.com/Ships/ ... ation.html ....
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http://www.researcheratlarge.com/Ships/ ... eBlue.html ....
Also, as was the case for many transitions in the USN when going from something "old" to something "new", the instructions said to use existing stocks of paint first. What we don't know is how much of the old paints were still "in the supply chain" at stateside bases and yards, contractor yards, and at forward bases, and when the new neutral gray paints replaced them.
Then there is when the Anti-Kamikaze program ramped up from directions for destroyers in late April 1945, throughout the war. For the FLETCHER class, the bulk of the Anti-Kamikaze Mods accomplished were done on the West Coast at USN and contractor yards. The majority of BENSON-GLEAVES classes had been based in the Atlantic. Starting in late 1944, units of the Atlantic-based BENSON-GLEAVES classes started to be sent to the Pacific in small numbers as the threat from Germany fell. Just as Germany surrendered, the Anti-Kamikaze mod program for the BENSON-GLEAVES classes ramped up in May 1945, prior to those units transitioning to the Pacific. The majority (but not all) of the Anti-Kamikaze BENSON-GLEAVES mods were done on the East Coast.
Out of 29 BENSON-GLEAVES classes units upgraded to the Anti-Kamikaze Mods (27 got the full upgrade with two quad and two twin 40-mm mounts, and two because of a shortage of quad mounts, had four twin 40-mm mounts), only five were done on the West Coast. Boston, New York, and Norfolk Navy Yards did the East Coast mods. The majority of these conversions were done in May-June 1945, with the West Coast units trending to be done after those. The further into the upgrades and repair of war damaged units process the closer to the transition from Blue-Purple paints to Neutral Gray paints.
Note; Verified with photo (yes or n/a)
Original Gleaves Group (12 units)
DD-423 Gleaves ... yes-NYNY ... 16 May – 8 June 1945
DD-424 Niblack ... yes-NorNY ... 6 May – 14 June 1945*
DD-429 Livermore ... yes-NYNY ... 29 May – 19 June 1945 NRT
DD-430 Eberle ... yes-NYNY ... 10 May – 4 June 1945 NRT
DD-431 Plunkett ... yes-BosNY ... 27 May – 25 June 1945*
DD-432 Kearny ... n/a-BosNY ... 6 May – 21 June 1945*
DD-435 Grayson ... yes-Todd Pac ..11 June – 28 July 1945
DD-437 Woolsey ... yes-NYNY ... 28 May – 18 June 1945
DD-438 Ludlow ... yes-NYNY ... 6 May – 4 June 1945 NRT
DD-439 Edison ... yes-NYNY ... 7 May – 4 June 1945
DD-440 Ericsson ... n/a-BosNY ... 6 May – 18 June 1945*
DD-443 Swanson ... yes-PSNY ... 28 April – 29 June 1945*
Repeat Benson Group – 12-40mm (11 units)
DD-600 Boyle ... yes-NYNY ... 1 May – (3 July 1945?)
DD-601 Champlin ... yes-NYNY ... 1 May – (3 July 1945?)
DD-603 Murphy ... n/a-BosNY ... 2 June – 10 July 1945*
DD-604 Parker ... yes-NYNY ... 1 – 22 June 1945
DD-608 Gansevoort ... yes-MINY ... 20 May – 18 August 1945?
DD-610 Hobby ... yes-Todd-Pac ..19 July – 4 October 1945?
DD-612 Kendrick ... yes-NYNY ... 1 – 22 June 1945
DD-613 Laub ... yes-BosNY ... 19 June – 29 July 1945*
DD-614 MacKenzie ... yes-BosNY ... 8 July – 13 August 1945
DD-616 Nields ... yes-NYNY ... 1 May – 3 July 1945
DD-617 Ordronaux ... yes-NYNY ... 1 May – (3 July 1945?)
Repeat Benson Group – 8-40mm (2 units)
DD-606 Coghlan ... yes-MINY ... 4 May – 4 July 1945*
DD-615 McLanahan ... yes-BosNY ... 8 July – 14 August 1945
Repeat Gleaves “Square-Bridge” Group – 12-40mm (4 units)
DD-497 Frankford ... yes-NYNY ... 23 May – 18 June 1945
DD-623 Nelson ... yes-NYNY ... 31 May – 21 June 1945
DD-624 Baldwin ... n/a-NYNY ... 31 May – 21 June 1945
DD-628 Welles ... n/a-PSNY ... 17 July – 2 September 1945?
The best I can tell you is that, depending on when (and maybe where) your modeling subject was upgraded to the Anti-Kamikaze Mod, will indicate the "probability" of which paints were used to repaint that ship. Also, many units upgraded, have few to no photos available showing their Ms 21 of Ms 22 scheme.
As best I can say, is make a judgement based on what you think.