Dirty Harry - S4-E5
Continuity mistake: When Dexter listens to Officer Lundy's tape recording, we hear Lundy say that the Trinity killer's weight is 190 to 200 pounds. When we saw him recording that, he said 200 to 220 pounds.
Dirty Harry - S4-E5
Visible crew/equipment: After the ambulance taking Deb to the hospital drives away, a crew member ducks down in front of a parked car in the background. (00:04:36)
Dirty Harry - S4-E5
Other mistake: When Lundy is shot and falls to the ground, there is no visible injury even though he is facing the camera. Later, Masuka says he was shot twice, once in the chest and once in the neck. The shooter was facing him. We should have seen the blood.
Dirty Harry - S4-E5
Revealing mistake: After the intro at the start, it cuts to Dexter passing the fire engine, and the next long shot with a firefighter lifting the yellow tarp is a flipped shot; note the backwards licence plate, sign, etc.
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.