Too many fakes out there to be buying used optics from unknown sources.
I personally dont buy stuff like tgat used. Trijicon warranty doesnt transfer with the device. They do that to combat the amount of fraud there is in dealing with the aftermarket trade of their optics.
Acogs have a certain rugged feel to them and pics are easily faked. The finish has a certain texture and the glass has and reticles have certain quirks that cant be seen in a pic but are dead giveaways on fake models.
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...