The devnagari scripts as transcribed are quite interesting, and difficult to read. I am no army expert but as a Nepali, here's what I came up with so far.
For the very first one pic titled Triggerguard, The markings are as follows
Ka 1
2 (unable to figure the second one)
44
Triggerguard Tang (U could be write about the translation Subunit 4 and no 34)
Jung 4
No
34
Long Leaf Khukuri
It reads
Shree Teen Chandra (with a picture of the moon=chandra meaning moon in Nepali) Singh 2126
In those days Prime Ministeres from the RANA clan (the aristrocrats as we refer to them in Nepal) were addressed as Shree Teen. This Khukuri might as well belong to one of the PM from the past.
Thank you for sharing the pics. And Good Luck in your search for the true and actual meaning.