Marine Private Cheryl Parks is shown walking through the gate to leave the base. Especially being a Marine Private, she would NOT have her hair hanging loose to her shoulders, and she would NOT have been outside, in any uniform, without a hat!
Nancy Grace, the author of the Hailey Dean series, appears as a frazzled food truck proprietor who is trying to take a break as Fincher and Hailey are placing their orders.
Not one of the supposedly Marine uniforms are legitimately rated correctly. The actor, introduced himself, as a LT; however, the rating insignia was incorrect. It was an enlisted rating; not officer.
Edit: Lt. Young is wearing the correct rank insignia. The bars he is wearing are flat black combat bars. By having no reflection like traditional, non-combat "brass" bars, it makes it harder for snipers to spot Marine officers, same reason you don't salute in combat zones.
Fincher states that the Marine motto, Semper Fi (Fidelis) means Always Loyal. Although Fidelis can translate to either Faithful or Loyal....any Marine or former Marine would know that as the traditional translation of Always Faithful.
The show is set in Atlanta, GA, but Fincher's car has a license plate on the front bumper. Cars registered in GA only have 1 plate mounted on the rear bumper.