WW2 stuff not in the book Doughboy to GI 52 ???

I have had the reference book "Doughboy To GI : US Army Clothing And Equipment 1900 - 1945" since I was a kid.  I liked watching old War Movies and was interested in the stuff the soldiers were using.  My Grandfather was also in the Army Air Forces during WW2.  My reference book was mainly just photos of one guy's collection of militaria and didn't have an example of every US Military issued item.  Sometimes I see something not in my extensive reference book.

I believe the green leather bag shown here in these photos is a Navy Landing Party Machine Gun Magazine bag used for both the Tommy Gun and the Greece Gun Sub-Machine Guns.  This bag is partitioned on the inside to hold the magazines.

However, I have been informed that this might be a Post-WW2 Hungarian AK-47 Ammo Bag.  But, why does it have United States Navy Markings?  I have seen examples of nations here on Earth copying other Nation's Military equipment.  Many Asian Nations copied WW2 era US equipment just to sell it as camping gear.  I have seen many former parts of the British Empire still using British style Ammo Belts and bags.  I really don't know why a Hungarian Ammo Bag would have US Navy Markings.  Maybe this bag has a fake marking, or the Hungarians copied a US Military Ammo Bag Design, or for some reason the US Navy used a Hungarian Ammo Bag.   I don't know everything.  I am just a guy trying to study artifacts, but sometimes people fake things just for money.  I do have a History Degree and am trying to be honest...