I'm not sure if the Sudetenland was a popular aspiration of pan-Germans back then.
Could go either way. Given that Bohemia used to be part of the Holy Roman Empire and the German Confederation the pan-Germanists might root for all Czech lands to be 'brought back'.
And while incidentally the Sudeten area might have been exempt on this postcard, it is obvious that pan-Gemans used to think big: