The doc the screen capture is from, 'Pacific Area Material' from 1945, states that it is based on the M67 spin-stabilised projectile, so it is certainly not a finned projectile. As mentioned it might be a typo, but I'm not going to spend a lifetime trying to find out. Plus being in the UK restricts my access to some of the harder to find US reference material.
As to later projectiles for the M27 and M27A1 105 mm recoilless guns, according to another publication (TM 9-1300-203 - Artillery Ammunition. Change 12, 1967) there's M323 HE, M324 HEAT-T, M325 WP smoke, M326 HEP-T and the M341 HEAT. The M324 round uses a spin-stabilised projectile like the M67. The M323, M325 and M326 rounds all have spin-stabilised conventional (other than the driving band) projectiles. The M341 round's projectile is fin-stabilised, with a very long tail boom attached to the end of which is a fixed-fin stabiliser assembly. The publication also puts the T42 designation as a previous one for the M323 HE, which marries up with the previous 1945 publication. It doesn't however give any of the other rounds' earlier designations. If someone has earlier versions (pre Change 12) of that publication, these may contain the required information. There's also 'TM 9-1300-204 - Ammunition for Recoilless Rifles from 1959, which uses portion of the ammo sections from the 'TM 9-1001' publication that seems to have covered recoilless guns. TM 9-1300-204 doesn't cover ammo for the M27 series, but the previous versions (1950, 1954 and 1955) TM 9-1001 publication may.
As far as my documentation states, 105 mm projectiles with flip-out fins come out with the M40 106 mm (really 105) recoilless gun, with the first adopted being the aforementioned M344 (T119E11).
As to the T43 designation, it could be anything as it's just an arbitrary designation given to something as it was being developed by the US Army prior to the use of the XM developmental designation. For example you can have many T1 numbers, one might be a rifle cartridge, another could be a food ration pack! You can of course have one T number item, which is made up of many other T number or even M number components.
