When Dexter is looking through an old notebook (10:05) you can see actual newspaper clippings from the Jeffery Dahmer case.
The birth date used for Walter Kenney (July 23, 1938) in the police database, when Dexter does a search on the name, is the same as the birth date of Ronny Cox, the actor who plays Kenney.
Ronny Cox co-starred in the film Deliverance (1972) with Burt Reynolds. There are multiple references to, and is named after, the movie starring Burt Reynolds.
Number 42 reference: Walter Kenney's storage unit number containing his trophies.
Ronny Cox (Walter Kenney) starred in RoboCop (1987) with Peter Weller. Weller appeared previously as disgraced former cop Stan Liddy.