The markings are,from what I can see,are "1" which is 1st Cavalry, the second mark is "E", which is Troop E and the final 3 numbers are the Troopers numbers,The markings were placed here on the comb so as to be read when in the scabbard.The inspector mark ,LTT, is from the late 1930s. If I am not mistaken Mr.Beardicon found it some years ago.
Respectfully submitted
Ed Byrns