Were there Jewish believers in Paul's early Gentile churches?
Yes. The early congregations were predominantly Gentile, but Jewish believers were present. Paul consistently went first to the Jew, then to the Gentiles when the Jews did not respond. Consequently, a smattering of Jewish believers existed in all his early little congregations, and archeology substantiates this presence.
Les explains that the congregation Paul addressed was predominantly Gentile, yet he says no doubt there were Jews in the early congregations. Paul would always go first to the Jew, and then, when he saw that it really wasn't going to reap a harvest amongst the Jews, he would go to the Gentiles. Les is convinced that in all of Paul's early little congregations there were a smattering of Jewish believers, and he thinks archeology substantiates that as well. He then moves to discuss women in the Church, noting that customs and environment change even though the Word of God does not, and that God mandated certain things for Israel because of their national customs.