Yup--Paul reiterates it more than once:
1 Corinthians 8:6----King James Version (KJV)
6 But to us there is but one God, the Father, of whom are all things, and we in him; and one Lord Jesus Christ, by whom are all things, and we by him.
Paul, nor the NT writers never included God the Son as the "one God" of the Biblical NT. That was reserved alone for the God and Father of Jesus Christ.
1 Peter 1:3---King James Version (KJV)
3 Blessed be the God and Father of our Lord Jesus Christ, which according to his abundant mercy hath begotten us again unto a lively hope by the resurrection of Jesus Christ from the dead,