Paul did the latter. However, since Paul certainly knew about predestination and election, this tells us something about how to deal with seekers. Paul didn't write about predestination and election for nothing, so we can infer that these concepts might normally come later on as part of the sanctification of the believer. No one comes to belief with everything in the Bible already thoroughly figured out. That's one unreachable goal of sanctification.
Do you suppose that Paul ever studied his own letters as we do today?