If my father was born in Germany but his parents were not, does that make him a German Citizen?
It matters whether they were German citizens, not whether they were born there. In short, if they were not German citizens, it is highly unlikely that he was.
Both of my grandparents birth certificates were destroyed during WWII.
Without paperwork proving they were Polish citizens, you have no chance of gaining Polish citizenship even if you do qualify (and it sounds like you do not).
What was the date of issue?
I'd imagine that that is going to be the final nail in the coffin.
I got my kids Polish citizenships
It's a strange parallel universe you live in.