Genealogy / Records from pre-1914 Będzin and Sosnowiec [10]

Hi everyone,

I'm doing some research on my Polish Jewish grandfather (born in 1907), trying to find out where he was born, and to find a birth certificate. The family originally came from Działoszyce, north-east of Krakow, but a genealogist I hired to look through records there found birth records for my great-grandfather, but not my grandfather.

More recently, I discovered some old family notes saying that my grandfather's immediate family had lived for a period in Będzin (just outside Katowice). I also discovered some old letters between my grandfather and a cousin living in Sosnowiec (next to Będzin). So I'm wondering if my grandfather might have actually been born in either Będzin or Sosnowiec.

Can anyone advise me where would be the best place to go to look for these birth records? Of course, I have checked every online resource I can think of (Ancestry, FaimlySearch, Jewishgen). But would the Polish state archives have these records? Does the fact that Katowice was part of Germany in 1907 complicate things?

Many thanks for your help!