I was not trying to upset anyone just observe certain aspects of the rifle in the pics the OP supplied as these rifles have been to timbucktoo and back who knows what happened to them this one may have just had the TR stamped on it then never got completed until an enterprising person perhaps decided to do it either in service or out of service.
I would tend to go out of service as it would be a plucky armourer to try and buck the system although they may have done it up on their smoko breaks!!!

That may be it Surpmil perhaps explains why the certain denoting stamp common to S51 factory completed "T"s is not there on the flat well there is one there but.......!