Factual error: When Dexter is reading the list of drugs found in the autopsy of the murder victim, one listed is "Cialopram." This is a misspelling of the antidepressant Citalopram; misspellings do not occur on drugs lists in toxicology reports, as they are computer-generated. (00:37:10)
Continuity mistake: When leaving his home at the end of the episode, he locks the door, then sees a big storm and walks back inside without ever unlocking the door. (00:49:30 - 00:49:52)
Answer: No, Harry is not the real father. While he did have an affair with Dexter's biological mother (Laura Moser), this was when she was his C.I. Dexter was already born at that point.