It is never a bad idea to resurface an older thread when new information becomes available.   Good post. 

Good finds. Always good to have extra scabbards/sheaths on hand. 

Question the age? It’s dated “41”. Also you definitely need to clean that vertigris off the metal components. It will rot the leather and ruin the value of your holster. Now if you don’t wanna do that you can sell it to me and I will do it.

Also, remember what kind of war it was. Trench warfare.  Painting your unit insignia would not really stand out as a target especially if the entire unit had their helmets marked the same way. When they got out of the trenches and ran or range walked across no mans land, a white star on their helmet, a pine tree, the red keystone etc etc  was the least of an infantry soldiers worries. They were targets no matter what. Not like fighting in a forest or a jungle.... where bright colors of any kind or uncovered white face with no cammo on it stands out like a beacon. If you have never seen it live, soldiers wearing cammo, if they dont wear gloves cover their neck and apply cammo face paint, particularly pale skinned folks.... Even though wearing a good cammo uniform, they stand out like sore thumbs in a forest environment. In WW1They were mostly flat out in the open. Exposed. And snipers were looking for NCO's and Officers.  So it didnt really make much difference if you had visible unit insignia back then. In my opinion....  

See above.

They werent exactly subdued... Just not painted all over. This 28th Division... bright red... Has a split chin strap to keep it on the  chin. Possibly combat or field worn? Its a giant guess unless it has a name and number. The keystone is on the side. That 37th engineers has a name and number in it. And its not overly painted, like the 3rd image just for example....

Subdued colors make sense. Especially in a combat environment 

Awesome helmets! 

So I can add 91st division to the pre armistice list?

Agreed, the basic or more subdued ones like the greens in the 91st and 4th and the basic reds in the 5th, 6th and engineer helmet are what were likely more used pre armistice.