Best regards to California from Prague, Czech republic, formerly Czechoslovakia.
The story sounds rational but I have are serious doubts about. It is absolutely sure that this piece is a "bohemian", this type of glass has been produced in Haida (Nový Bor) region. After Munich agreement in November 1938 this part of Czechoslovakia felt German hands and was connected to Germany. The rest of country became be the Protectorate of Bohemia and Moravia in March 1939. The perion between November 1938 and March 1939 is so called 2nd republic, and residual part of inland had a name Czecho-Slovakia, before and after WWII always Czechoslovakia.
So the region of Haida with more than 50 percent of German spoken Czechoslovakian citizens was really part of Germany. What is very unclear for me is the usage of English for designation of origin. At that pieces formerly having Czechoslovakia mark were stamped "Sudetenland" or simply Deutschland, the export of glass to abroad was minimal and prevented by British "Enemy Act".
My explanation for "Made in Germany" is following.
In 1945 after the war the parts of Czechoslovakia, including Haida region were connected back to Czechoslovakia and all German spoken Czechoslovakian citizens (about 3 mio) had been expelled from Czechoslovakia to Germany. Many of them were glassmakers, the lack of glass-specialist was big problem for renewed Czechoslovakia. I discovered yesterday, that with this glass makers was transferred to Germany also know-how of making Egermann's pieces. The same had probably happen with this white overlaid clearly "bohemian" decorated piece.
I suppose that this piece has been produced after WWII anywhere in Western Germany by expelled Czechoslovakian Germans.