Real Eames has NO exposed screws. Yet this video shows screws under the armrest  

The "no exposed screws" refers to how the cushions are secured in the outer shells of the chair. On Plycraft/Selig loungers, which are what many neophytes mistake for the real thing, the cushions are fastened in place with small screws that are very visible.
Plycraft/Selig shells are also bolted to steel connectors and the bolt heads are visible on the outside of the shells.
This doesn't apply to modern day knockoffs made in China. There are other ways to tell those from the real thing.