When Furillo arrives at the store where hostages are being held, he tells all the cops to holster their weapons, and they do. A couple camera shifts later, all their weapons are back out before anything happens to make them take their weapons out.
Just after the 25 minute mark, as Esterhaus walks into the interrogation room with bags of food.
When he knocks and opens the door with his empty right hand, he has two brown bags in his left arm and (presumably) the small white bag in his left hand.
As he is seen entering the room, the white bag is suddenly on top of the brown bags in his left arm and he's holding the bags down with his chin. No time for such a switch.
Sergeant Esthaus' collar devices are upside down. The collar devices would be in the same orientation as that as what appears on his sleeve.