Your sentence makes it sound as if Paul only learned of what you call
“the resurrection stories” because various people had personally told Paul that they had seen a risen spirit of Jesus. As if those people were the source of Paul’s belief in a resurrected Jesus. But that is of course wrong, as Paul’s letters make abundantly clear.
In his letters, Paul makes very clear that his source for belief in a risen Jesus, is OT scripture. Not anything any believer may, or may not, ever have said to Paul about their own spiritual visions.
No doubt in the 1st century, early Christians were constantly claiming to witness all manner of religious spirits. Not just visions of a spiritual Jesus, but all sorts of angels, demons, devils, gods & God, spirits of all sorts. Even today, in fact every day, thousands of Christians swear to see visions of Jesus, God, the Virgin Mary etc.
But be clear - Paul’s letters say quite clearly that his resurrection belief is obtained according to scripture as a matter of faith and revelation from God. Not because he did not know about it until various people told him they had seen a vision of Christ risen from the dead.
See the relevant quote below -
http://en.wikipedia.org/wiki/Conversion_of_Paul_the_Apostle
The conversion in Paul's letters
In his surviving letters, Paul's own description of his conversion experience is brief. In his First Epistle to the Corinthians,[9:1] [15:3-8] he describes having seen the Risen Christ:
For what I received I passed on to you as of first importance: that Christ died for our sins according to the Scriptures, that he was buried, that he was raised on the third day according to the Scriptures, and that he appeared to Cephas, and then to the Twelve. After that, he appeared to more than five hundred of the brothers and sisters at the same time, most of whom are still living, though some have fallen asleep. Then he appeared to James, then to all the apostles, and last of all he appeared to me also, as to one abnormally born.
— 1 Cor. 15:3–8, NIV