Absolutely I am saying this. Paul was not saved until Acts 9. How could his message be anything BUT newer than Peter's or Stephen's? Their message concerned a kingdom of believers. Paul message concerns a Body of believers. The Church the Body of Christ. Look back at the first part of Acts, before Paul was saved. Peter did NOT preach on the day of Pentecost that Christ died for our sins, was buried, and rose again the third day. Peter was preaching the Gospel of the Kingdom to Israel. Just as Christ instructed him to do.
What is the source of that teaching? I seem to recall hearing that when I was a Baptist - I was admonished to have nothing to do with it.