Found the book in my lunch break, but it is very sad - nearly 500 pages and hundreds of pics, but nothing about buttons or badges produced for foreign armys after 1945.
I visited some manufacturers in Luedenscheid in the 1990s, Assmann, Deumer, Linden and also the city museum. I saw sample boards with insignia for allied armies, and older employees told me about the time after the war.
Perhaps they "had" to produce these insigna as a kind of reparation or compensation ? I will try to find out more ........
Interesting that there are still buttons available, may be from old stocks:
https://berlin-military.com/Corps-of...ineers-Knoepfe
Regards
Markus
.... and here a lot of US-Military insigna made by Assmann after the war .....
https://www.usmilitariaforum.com/for...ssmann&quick=1