Virtually everybody, when they recount an incident, tell their side of the story.That’s not to cast aspersions on your son’s honesty, that’s just the way people are.
If your son’s story exactly matches the truth, he seems fine to me.
In some cases, you really don’t want/need to seek out the other side of the story. This seems to me like one of those times. Mainly because it would escalate what should maybe just be let go. But I only know what I read in your post, so I don’t really know.