When Tony pulls the can of paint from the back-pack, it has an orange spray top. When we see him from another angle, the top is a flat orange tab.
When stating there is no NSN number, Abby says it's a National Stock Number, NSN stands for NATO stock number, and is used throughout all members of the North Atlantic Treaty Organization.
Abbey states that "whenever the Marines accept equipment from a manufacturer, they stamp it with the National Stock Number". The NSN is the equivalent of a civilian part number. The vests would never have been shipped to the government with the ID plate blank, regardless of whether or not they were defective. If the vest failed the manufacturer's test, the ID plate would never have been installed.
On the check used as evidence, the printed last name on the top of the check is Linn. However, the signature spells it as Lynn.