Seems a bit different than the others I have, and there is no shock protection as I can see, this made me wonder if it could have been replaced.
This image from the Ranfft archive shows what appears to me to be the same movement with minor differences. The movement in the image is also not equipped with shock resistance. Yours appears to me to be equipped with a bi-metallic, temperature compensating balance wheel which might mean it is an older movement than the one in this image. But it looks okay to me. But i’ve Been wrong before. http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&2&2uswk&Longines_27_0
Firstly, the caliber shown above is a 12.68N from the early 1950's. Secondly, the vast majority of 6T's have shock protection. Thirdly, the style of balance cock shown above is more typically found on early 12.68Z's from the 1930's. It seems likely that it has been replaced. I would have expected to see something like this (below). Lastly, the balance wheel above appears to be mono-metallic, not bi-metallic.
@DirtyDozen12 - thanks , you confirm my suspicions. I have a lot to learn about these still but it looked nothing like my other of the same caliber. And according to the movement number shock protection should be in place as this had become a standard at that time as far as I know.