FWIW, there is a long history of troops making knives out of whatever they can find. Navy personnel made all sorts of neat knives during WWII, and other troops make knifes out of broken bayonettes, kitchen knives, or whatever they can find. Some are very crude, others are very well made and effective. The one OP has looks like a great pig sticker type knife, and I would be pleased to have it in a collection.
A close friend of mine has a knife that was made out of the tip end of a broken Katana. The blade is 8-9" long, and it is obvious where the blade came from. It is really cool folk art from WWII.
I look at many of these types of knives as trench art, or folk art types of knives. Many have wonderful value from the folk art/trench art perspective.