Hello, the time frame for US Zone (and British and French zone as well) can be narrowed down: May 1945 to October 1949. After that the two German states were founded and tecnically the three western zones merged to form the FRG (i.e. West Germany), the eastern (CCCP-occupied) zone became eastern Germany (GDR).
Berlin stayed an occupied city until German reunification and never was an official part of either western or eastern Germany (though the Russians saw this quite differently).
So >Western Germany< was used after October 1949, in some cases till German reunification on October 3rd, 1990.
For "Made in Germany " there is a nice article on Wikipedia: Made in Germany was first used for imports to Great Britain in 1887.
http://en.wikipedia.org/wiki/Made_in_Germany" onclick="window.open(this.href);return false;
Best wishes, Bahner