When Amy leaves the hospital room she is wearing her detective badge, she got promoted to Sergeant in the previous season.
Pam tells Jake that her college roommate dated the brother of Steve Guttenberg. Steve Guttenberg has 2 sisters but no brothers.
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.