When Mike begins his cover as an army reserve, he is wearing aviator sunglasses. When Paul sets down the bullets, Mike is off-screen for a second, and when he's back on-screen, the glasses have suddenly disappeared.
The portrayal of a USMC reservist is inaccurate in several regards. First, the haircut; no Marine, even a reservist, would have hair that long. Second, Marines are not permitted to wear their camouflage uniforms in public, and wearing just a T-shirt without the uniform blouse off-base is even more unlikely. Even a rogue reservist selling black-market arms/ammo would not flout regulations in this manner as it would draw undue attention. Finally, there are no 'quartermaster' units in the USMC, making his cover story even more unlikely.