Okay, here is what I was able to dig out on Tadakatsu.
Tadakatsu's real name was KOKETSU, Minoru. He was among the 232 gunto smiths worked in Seki Tanren-jo Co. during WW2. As you may already know, Seki Tanren-jo Co. was a forge created as a subsidized company by the city of Seki in Gifu Prefecture (old Mino province). Their aim was to boost the city's severely declining economy by participating in the "Tan To Ho Koku [serve the country by forging swords]" pro-war movement that started right before WW2.
According to the official record compiled in 1944, Tadakatsu officially joined the forge on May 7, 1943, and worked as a gunto smith till the end of the war. Unfortunately I don't have any other information on this smith, thus whether or not he was actually an Army Jumei Tosho that also produced real gendai-to is unknown. Since I could not find any other information on Tadakatsu in any of my reference books, my guess is that he was not an official army jumei tosho but was merely one of the Seki smiths who had mostly been making kitchen knives and carpentry tools before Seki Tanren-jo Co. opened...
Of course, that does not mean that the particular blade in your possession is a mill steel, oil quenched Showa-to of inferior quality (which will not be considered as a true Nihonto under the current Japanese laws). Actually I can see from the photos that the particular blade would probably be considered a true gendai-to (by the legal standard of the Japanese Customs) and be appropriately registered so, if ever brought into Japan.
Contrary to an old misconception still perpetuated amongst Nihonto collectors in the Western world, today's Japanese officials (who are commissioned by the customs to examine/determine if a blade to be imported into Japan is a real Nihonto) are better educated on Showa era gendai-to and interested in preserving them. So if you use today's more lenient standard held the Japanese officials, the blade should be considered a real gendai-to that can be registered in Japan. (Though I doubt if the blade would pass NBTHK's Hozon shinsa like the blades made by Emura and Ichiryushi Nagamitsu...)