66 and 67 come after 63.
Yes. Read the entire passage of John 6:41-71, and you will see that after Jesus explained the metaphor, and that only God would determine who would come to Jesus (and thus life), many left Him.
Read the entire section, literally. Keep the verses in order, consider the context and the preceding verses. It's pretty clear:
Jesus stated that you had to eat the Bread of Life to live forever. He said He was the Bread. And then He clarified that it is Spirit and NOT flesh that gives Life, and that His words were the Spirit and thus Life.He stated that only those granted by God would come to Him. Some of His disciples found this troubling, and left. The Twelve stayed with Him, though.
Is that not a fair reading and summation of the passage?