Hello all,
I have this Wurttemberg stamped envelope in my collection.

As you can see, it has two embossed stamps on it. The top stamp is denominated 1 kreuzer and the bottom stamp is denominated 5 pfennig. In 1875, Wurttemberg changed currency from kreuzer/gulden to pfennig/mark. So, my question: Is the 5pf stamp a "surcharge" revaluing the envelope from 1kr to 5pf due to the currency change? Any information about this envelope you can provide will be greatly appreciated.
Regards, Robert