Santiago is wearing 2 citation bars that are not issued by the NYPD. Also, NYPD regulations require that the American Flag bar be worn as the highest citation bar - something Santiago would have known.
Several of the commendation bars worn by Peralta and Boyle are not issued by the NYPD. Also, Boyle is not wearing the Medal of Valor he earned the previous season.
Captain Holt wears his Commendation breast bar above his World Trade Center Breast Bar. When the WTC bar is worn, it is worn above all other medals, but below the American Flag bar.
Several of the commendation bars Captain Dozerman wears are not issued by the NYPD. Also, Dozerman's commendation bars lack the black "WTC" commendation, given to all NYPD officers who served on or in the wake of the 9/11 attack on the World Trade Center.
The Vulture is also wearing his American Flag bar out of order. NYPD regulations require that it be worn as the highest citation bar. Not that the Vulture would ever care.
At the funeral, Terry is wearing a regular Detective's shield rather than his usual Sergeants shield.
Lieutenant Singh is wearing no rank insignia.