Note the Lot number - FA X30 1844A. Col. Frank Hackley has confirmed the designation and the details of their manufacture. I’m not sure when the cartridge was designated the T104E2 but it likely would have been in 1953 or 1954. It became the M59 upon adoption of the LR cartridge as the NATO standard.
Also, if you’ll look at your “T” lists, you’ll see the two entries - one for T65E4 and the later for T104E2.
I also have a photo of the so-called T65E5 cartridges but was not going to post it because of the low level of interest in these cartridges.
I don’t claim to know anything about these cartridges. If you think I’m wrong, or have other information, please post it.