"Did Jesus refer to his Father as the one True God or not?"
No, He called Him the only true God, the only One in heaven, while the Son and true God was upon earth. Before the Son came down out of heaven, they had been One in heaven from everlasting. And now, having returned to heaven, the Son and the Father are once again One for everlasting in heaven.
The One and Only true God is a false construct of unitarians that reject the true God coming down out of heaven of His own volition and power,
and returning to heaven the same, only now a resurrected Man Christ Jesus in heaven once again with the Father.
"And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven."
The Son did not come from man, but as a man He came from heaven. He was the 2nd Adam, because He had the uncorrupted blood within Himself on earth, even as Adam had from God. Being the 2nd Adam was not because He came from man.