Could this be a bigger upset than the Colts Jets AFC championships in the 60s?

The Colts and Jets didn't have any AFC championships in the 60's. In 1969 they played in Super Bowl III. The Colts were from the NFL and the Jets were from the AFL. The Jets won, causing the two leagues to merge into the NFL as we know it today. And no, this was not anywhere near as close as upset as that game.