Made before August 1945 or post was souvenir? Came with other mint flags with envelopes addressed to LtCol. In 1947 from War Department so he must have sent these hone from Nagoya 

Hard to tell when manufactured, but definitely sent back to the States from Occupied Japan.  Mitsukoshi was/is a large Japanese department store in Tokyo that sold/sells all kinds of things.  Again, no telling when the flag was made (during or post-war), but since the Mitsukoshi envelope is printed in English, it's a good bet that it was made post-war. 

The envelope is separate it had a kimono and slippers 

Then scratch my response...  With that context, there is no way to tell whether your flag is wartime or post-war manufacture.

I’m sure he sent them home hopefully he found them from wartime stock