How would Peter have responded to Cornelius if he had understood Paul's gospel of grace?

Les explains that Peter was still basically a law keeper and had not comprehended Paul's gospel of grace. At the vision of the sheets, Peter said, 'Not so, Lord,' refusing to eat unclean animals because he had never gone contrary to the law and ate kosher. At Cornelius's threshold, Peter told him it was unlawful for a Jew to keep company with a man of another nation. Les says if Peter had understood Paul's gospel of grace, that thought would not have crossed his mind; he should have been thrilled to enter the house of a military officer. But it was bugging him as a good Jew, and according to the law he could not go in. God had made it plain that this was what He wanted. This was part of the controversy where Jewish emissaries from Jerusalem undermined Paul's congregations, including Corinth, and questioned his apostleship because he lacked official recognition from Peter and the eleven. Paul insisted he did not need their recognition; he received his from the Lord in heaven.