Ryan,
I agree that these Hōkoku Reisen were all assigned to 252 Ku based on the wide fuselage bands toward the rear of the fuselage. Here is the latest info and translations I have for these.
Nakajima-built, Manufacture Number 5451, Completion Date 2-11-? (No. 75 of 80 produced in November, 1942)
報 國 第 1053 號
( 全 南 海 苔 號 )
Patriotic Gift To The Nation Number 1053
(Jeonnam Seaweed) - Jeonnam is a province in the Southwest part of South Korea that is known for cultivation of seaweed for human consumption. The donors were businesses associated with this product.
Nakajima-built, Manufacture Number 5459, Completion Date 2-12-? (No. 3 of 96 produced in December, 1942)
報 國 第 1045 號
( 内 外 印 刷 號 )
Patriotic Gift To The Nation Number 1045
(Domestic & Foreign Printing) - The Google translation is (Inside & Outside Printing). But, an example I saw was printed in both Japanese and French, so I think (Domestic & Foreign Printing) is a better translation.
Nakajima-built, Manufacture Number 3471, Completion Date 2-12-? (No. 15 of 96 produced in December, 1942)
報 國 第 1033 號
( 第 二 青 島 綿 糸 布 號 )
Patriotic Gift To The Nation Number 1033
(2nd Tsingtao Cotton Cloth) - The donors were Japanese-owned textile mills in Tsingtao, China.
The Hōkoku donor inscriptions were all applied Nakajima-style, which differed significantly from those applied by Mitsubishi. All three listed above were part of a large production block of Hōkoku Reisen that ran from at least Hōkoku 1054 through 1032, and probably included several more at each end of the range. It appears that Nakajima applied the donor inscriptions in reverse order to the Manufacture Numbers, possibly as a way to make it more difficult to determine production figures based on the Hōkoku numbers. You could probably make a good guess at the Completion Dates based on the production information I included above.
Thanks,
Ed DeKiep