Woaw! Terry (Bagman) thanks for this breakthrough.
Your research seems to explain everything - I think this mystery is now solved. I always thought these were outright fakes, but given all the points brought up this makes a lot more sense, I think both sides can be satisfied.
Is it possible that the shovels are also from the same era? Is it proven 100% they are WWII production? I looked for hours trying to find a WWII photo of a marine with this "re-enforced" shovel to no avail...
The shovels are ww2 period pieces, unless you see a marine with one in his hand using it and you can see the back of the shovel it is hard to see which type of t handle they are using