I can read most data but not all. Be sure that your grandfather is born German.
Can you post your translation to the topic tłumaczenie ? 🙂
Other People can read more than me.
You can discover your mystery easily by asking the USC with the number mentionned 1662/96 (I guess you already now that)
I think the marriage record will bring useful informations for you.
Well I am curious but really the nationality of your GF is history. You just want to know if he was german or polish? What is so important ?
Just a information: There is no automatic change of his nationality unless the Poland Republic will be back after 1945. He is born German and remains German.
Wait to read the marriage record..