No it's not...it was germanic before (Rugians) and again after the Slavs left.
No, Slavs didn't leave those territories, they were conquered in rather bloody wars and then marginalised. German expansion was luckily stopped in its track at one point when they encountered more established state structures (Polish state).
Regardless, BB, what is amusing is that you won't acknowledge that:
a)Germanic influence vanquished after Slavs settled in those territories. They were scarcely populated to begin with, after Germanic tribes went off to plunder Roman civilization there was even fewer people there and Slavs did find mostly deserted lands
b)Germanic is not not equal to German. Similarly, Slavic is not equal to Polish! You falsely assume that tribes that inhabited today's Poland in 2nd century are ancestors of Germans. They weren't, at least most of them weren't.