Great, thanks Zifir!
That matches the 1913 on the scabbard then. So this makes the large yataghan the latest I have seen, and an example of 20th century production
This also matches what Sancar and others have said concerning these monster yataghan with T-pommel being more for show. The craftsmanship is quite poor, despite the large quantity of steel.
I will take better pictures of the inscription on the bottom one tomorrow.
Emanuel