Hi, Do you have a copy of George's death certificate? That should say where he was born. The quality of the info depends upon the person supplying the information. If they only knew the state, that's what they would have reported. But maybe they knew the city and state.
Information about how to order a copy of an information death certificate can be found at Alameda County's Official Website, http://www.acgov.org/auditor/clerk/http://www.acgov.org/auditor/clerk/ .
Do you have a copy of George and Isadore's marriage certificate? It's probably an entry written in a large journal since they were married in 1870. I'm not familiar with who to contact in New York.
I don't know if their children's birth certificates would have where George was born or not. Successful Searching!