Was Peter the one who brought the Corinthians to salvation?
No. According to the context, Peter was not instrumental in bringing the Corinthians out of paganism or to salvation. Paul would have given Peter an opportunity to speak to the believers at Corinth, but the group that clung to Peter did so out of Jewish affinity, not because he led them to salvation.
Les explains that although Paul would have been the first to give Peter an opportunity to speak to the believers at Corinth, he does not believe Peter was instrumental in bringing these people out of paganism and to salvation. Nevertheless, a group at Corinth clung to Peter rather than Paul or Apollos. Les suggests this group was the Jewish element, since Peter had been steeped in Judaism, was located at Jerusalem, and was connected to their background, temple worship, and all that. This caused a division, which Paul considered a problem.