"Theater knives" were hand crafted or modified by servicemen around the world during WWII using whatever materials and tools they had at hand - wherever they were. The following is my recollection about my Dad who went in the Army in very early 1942 - then made a career out of it.... I'm sure our country had many, many like him from modest circumstances he hit the ground running....
As a kid I accompanied my Dad to our local post hobby shop on many occasions when he was assigned to Redstone Arsenal in the sixties. Like most larger posts the Army had a good sized hobby shop at Redstone (a big area for automotive stuff, and another generous one for woodworking/craft work). That handle looks like something he would have been able to make (always with available materials....). Back before I was born, during WW twice there were many, many service members that came into the service with great woodworking, metal working, and similar skills - all using whatever materials were available... In my Dad's case he'd been a work crew supervisor in the late thirties working for Pan Am building new airstrips in both South America and Africa (back when a work crew might have had one or two pieces of heavy equipment - and a crew of native laborers with lots of hand tools..). When the war got started and he joined up (volunteered for the draft is how it was done...) he was exactly what the Engineers were looking for.. That was a time when mechanics and other maintenance types routinely re-built or refurbished broken parts for most types of gear - if at all possible, since "spare parts" were a great luxury if you were in the back of beyond somewhere and had a job to do...
Looking back on it all these years later (and long after he'd passed away in the early nineties...) I realized that not only was he very skilled with his hands (he could make a piece of furniture from scratch - with no nails or screws until the finishing hardware, lay a line of brick perfectly straight, tune a car engine by ear... but back then he was actually the commander of many post facilities (from a private to a lieutenant colonel over a 28 year career)... Funny thing, though, on weekends he dressed like a common grease monkey and you'd have never known his rank - unless you needed to know... Not bad for a depression era kid who came out of dirt poor beginnings in north Alabama.
I'll miss him until I'm no longer around....