To be clear so we can all understand just what you're speculating about the apostle Paul, are any of his beliefs POST-conversion thought by you to be "gnostic?"
Or just some of his PRE-conversion beliefs when he was universally-recognized to be a chief tormentor of Christians?
It is thought so by some highly educated people. You will have to do your own research on this. But to answer your question: his earlier Epistles contain many Gnostic words and phrases. His later works don't but are probably forgeries. Fingers point at +Irenaeus.
One thing you will have to understand is that the Church needed a way out, because it was dying quickly in Israel. +Peter came back from preaching to the Jews, which was a complete failure. Even basic knowledge of Judaism would make you understand why (for starters, Jews do not believe man needs grace to be righteous).
It was +Paul who had the flexibility needed to make Christianity acceptable to Gentiles. He even reprimanded +Peter publicly for his resistance to change Judaic practices or to eat with Gentiles. Without +Paul, Christianity would bee a dead religion.