It is definitely the 346.1, good eye SmartOne. The coin is actually fairly interesting, as it represents the time right around when the Duke mentioned on this coin (Georg Wilhelm) saw his younger brother, Ernst Augustus, who should have inherited nothing, earn an Imperial Electorship, and go on to unify several of the dynastic territories formerly held by their ancestors.
Georg Wilhem, on the other hand, led a colorful but less successful life, and after an somewhat rough campaign against the Danes over a minor territory, ended up legitimizing the daughter of his mistress as his "successor" by marrying her to his nephew, Georg Ludwig. Georg Ludwig later went on to become George I, King of England and Elector of Brunswick-Lueneburg.
