I believe he was, and is the God Yahweh, and the God from Genesis and all of the other OT. Why? Several reasons. For one, scripture says so. John 1:1-3, John 1:18, John 5:37, John 6:46 states:
John 1:1-3,
"In the beginning was the Word, and the Word was with God, and the Word was God. He was with God in the beginning. Through him all things were made; without him nothing was made that has been made.
John 1:18,
"No one has ever seen God, but the one and only Son, who is himself God and is in closest relationship with the Father, has made him known."
John 5:37,
"And the Father who sent me has himself testified concerning me. You have never heard his voice nor seen his form,"
John 6:46,
"No one has seen the Father except the one who is from God; only he has seen the Father."
So we learn from these four verses that Jesus is God, who was always with God the Father, and he created everything we see along with the Father. We also learn that nobody has ever seen God except for Jesus. Even Jesus himself states that nobody has seen God the Father but him. But wait! Adam and Eve saw God! Isaiah saw God! Ezekiel saw God! Countless people of the OT saw God! So, either Jesus is lying or Jesus is stating that he is the mighty Yahweh, the God of the Old Testament that created the heavens and the Earth and all we see around us. The Jews knew what Jesus was saying when he stated these things along with when he said in John 8:58:
John 8:58,
"Before Abraham was born, I am!"
To which the Jews tried to stone him for because God called himself "I am" in Exodus 3:14.
Exodus 3:14
"God said to Moses, "I AM WHO I AM. This is what you are to say to the Israelites: 'I AM has sent me to you.'"
So what do you think? Was Jesus the God of the Old Testament? Or was Jesus just plain a God along with the Father and God the Father is the God of the OT? Tell me what you think. I'm curious.