Well, I decided to do a little research on E8N Dave myself, and learned several things-- none of which makes sense for the Dave/Yamato pairing, but I suppose anything in wartime is possible. Here's what I learned:
1) The Nakajima E8N Dave was developed as a lightweight reconnaissance seaplane in 1938 for the Japaneses navy, and was heavily used as the IJNs primary reconnaissance catapult aircraft up to mid 1942. It was also used as a training aircraft post 1942. 755 were produced, and one was even flown by the German Auxiliary Cruiser Orion, being the only Japanese catapult aircraft flown off a German ship during WWII. According to Wikipedia, The only battleship listed as having actively flown the E8N during any major Pacific WWII action was the Battleship Haruna, which flew a Dave during reconnaissance missions in the Midway Campaign in 1942. After that, the Dave was replaced by the FM1 Pete or the Aichi E13 Jake.
2) Yamato was launched on Dec 16, 1941, and sunk on April 7 1945. It went through several major campaigns in 1943-44, but was torpedoed and sent to Kure for repair, largely staying in the home islands until 1945, when it sortied on its last suicide mission to Okinawa. The Dave would have been almost obsolete by the time the Yamato reached service. It's hard to believe Japan's most modern Battleship would have been equipped with an obsolete fabric covered aircraft while other older ships were employing all-metal recon aircraft.
3). Wikipedia lists either 7 E8N Daves or the E4Ns as the two types of standard equipment on the Yamato, the E4N being an even earlier fabric covered seaplane developed in 1930, and obsolete by 1940-- so this reference is a bit suspect, since the Yamato wasn't commissioned until December 1941, after Pearl Harbor. Even more suspect when the Wikipedia cross reference to the Wikipedia E8N Dave entry said it wasreplaced in front line service by 1942, and the last use by a Battleship was at Midway in 1942.
4). I have several Japanese language books on Japanese Navy floatplanes, and a "pretty good" guide entitled "The Air Force of the Japanese Imperial Navy" by Eduardo Cea. None of these books appear to show the E8N Dave or it's predecessor the E4N as floatplanes on the Yamato during WWII, although it lists them as primary aircraft for other ships during the Sino-Japanese war of 1937 and up to 1942. The Cea book shows the Yamato as carrying 6 FMI Petes or E13 Jakes, with different tail markings than those on the kit box (but that may not be unusual, as tail markings changed frequently as the war went on). Finally, the codes on the kit aircraft tail seem to be from the Battleship Mutsu in 1942, which was changed from "AII" to "AIII-1" in 1942, according to the Cea book. The Yamato's aircraft tail codes are listed as "AI-1", while her sister ship Mushashi was "AI-2" (I'm not saying this book is accurate by any means, as it's primarily a color profile book, and although it appears well documented, the author fails to cite specific references for his color schemes, even though they are well executed, but appear a little disorganized in presentation).
5) the silver paint scheme on the kit box seems to indicate an early or pre-war scheme, which doesn't make sense if it was based on the Yamato, commissioned in December 1941.
Having done this research with my limited resources and " suspect "Wikipedia" entries, I'm not claiming these aircraft weren't on the Yamato, but it doesn't make sense based on operational dates, colors and tail codes. But, Hasegawa does some pretty good research, and being a Japanese company, I suspect there's a backstory as to why they are calling the Dave a "Yamato aircraft". I just hope it's not based on the Wikipedia references. Perhaps someone will review this kit and see what the instructions say about the markings.
VR, Russ