The Scriptural record: The Twelve Apostles were baptized by John the baptist before they were yet called by Jesus and had first believed in Him. They hadn't even been introduced to the Lamb of God! Their's was a pre-faith baptism and their only baptism as far as we know. There is no record of their re-baptism post-faith. That given, their one-time, pre-faith baptism, by God's grace, was indeed effectual unto their salvation through faith. It seems their subsequent faith in Jesus confirmed the sign and seal of their baptism given by God under John, which flowed from God's sovereign and wholly gracious election in Christ. They didn't choose Jesus and then announce their choice and commitment via baptism. They were baptized... and Jesus their Savior having already chosen them, effectually called them to Himself (John 15:16; Eph. 1:4).