You are exactly right. Paul wanted to run what he taught past the Twelve (plus James) for their inspection and approval. This was his stated purpose.Nothing in the passage indicates that it was Paul's intention was to teach THEM anything. Paul went to the most influential and respected leaders to join forces with them against a common enemy - the Judaizers. In the end the Twelve did not say any converts had to be circumcised. They "laid no burden upon him"and his converts but only wanted Paul to remember the poor.
As you say, if Paul had received some new revelation they disciples would have been in no position to judge it since the only gospel they knew was the one taught to them by Jesus.
What a load of dung!
Paul went up BY REVELATION and communicated unto them "that gospel" that He "preached among the Gentiles". What's the point of communicating "that gospel" or even saying "that gospel" if it were the same gospel?
They added NOTHING to Paul, but contrariwise...(that means to the contrary, Paul added unto them)! It was then and not before then that they "perceived the grace" that was given to Paul. Read it for yourself and believe IT.
Galatians 2:1 Then fourteen years after I went up again to Jerusalem with Barnabas, and took Titus with me also.
Galatians 2:2 And I went up by revelation, and communicated unto them that gospel which I preach among the Gentiles, but privately to them which were of reputation, lest by any means I should run, or had run, in vain.
Galatians 2:3 But neither Titus, who was with me, being a Greek, was compelled to be circumcised:
Galatians 2:4 And that because of false brethren unawares brought in, who came in privily to spy out our liberty which we have in Christ Jesus, that they might bring us into bondage:
Galatians 2:5 To whom we gave place by subjection, no, not for an hour; that the truth of the gospel might continue with you.
Galatians 2:6 But of these who seemed to be somewhat, (whatsoever they were, it maketh no matter to me: God accepteth no man's person
for they who seemed to be somewhat in conference added nothing to me:
Galatians 2:7 But contrariwise, when they saw that the gospel of the uncircumcision was committed unto me, as the gospel of the circumcision was unto Peter;
Galatians 2:8 (For he that wrought effectually in Peter to the apostleship of the circumcision, the same was mighty in me toward the Gentiles
Galatians 2:9 And when James, Cephas, and John, who seemed to be pillars, perceived the grace that was given unto me, they gave to me and Barnabas the right hands of fellowship; that we should go unto the heathen, and they unto the circumcision.