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you can still contact aota [aoata mituhiro] for a copy. google his name and or "full gear". if i am not mistaken, the price is appx $200. the book is invaluable for all of the info aota has put in it, and covers all types of flight gear, from the 1930s through the 1970s. in a few minor areas his info is incorrect or incomplete. the text is in japanese, but the listings, dates, and makers are in english. a copy should be in every flight jacket collectors library. he has also written what is the definitive book on zippers.
To be honest a always kind of like the dirt, unless its a big dollop of tomato Ketchup dropped out the back of a burger at a recent bbq!, so I say leave it but its your call.
All the best
Stu
Don't wash the patches! It gives the jacket the aged, authentic look it should have. A lot of people try and get that look on patches by dirtying them up and sanding them. You got the real deal there so leave it as is and enjoy!