The gospel Paul preached to us is not the gospel Ananias preached to Saul. It was afterwards, after Ananias was sent to Paul that the Lord revealed to Paul that gospel he was to preach to the Gentiles – Galatians 1:11,12; 2:1.
By God using Ananias to go to Paul, there is continuity or cohesion of the two programs of God in the sense that Paul did not just show up, separate from the Kingdom Saints with a separate Gospel and ministry to the Gentiles. He first himself believed that Jesus is the Christ and taught this fact at Damascus. Afterwards God calls him out to Arabia and gives him the gospel of grace, the gospel of the uncircumcision. As Romans 1:1 says, “Paul, a servant of Jesus Christ, called to be an apostle, separated unto the gospel of God.”
When exactly Paul was saved is not told us. What Ananias told Paul to do did not save Paul, at least not the baptism. Certainly “calling on the name of the Lord” did. Baptism was the step of faith in the Kingdom gospel, but when Paul wrote Romans 10 he said:
”But what saith it? The word is nigh thee, even in thy mouth, and in thy heart: that is, the word of faith, which we preach; That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved. For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation. For the scripture saith, Whosoever believeth on him shall not be ashamed. For there is no difference between the Jew and the Greek: for the same Lord over all is rich unto all that call upon him. For whosoever shall call upon the name of the Lord shall be saved. ”