Need help w/possible fake LV

[Incurable]

I don't know if this can/will go anywhere or not but... I work with a guy who was sporting what appeared to be a 16610LV today. He claimed he bought it at an undisclosed price but WAY cheaper than it's actual worth. He was being rather evasive about how much and where he bought it... He claimed the serial number appeared correct and that he had removed the case back and the markings inside the back appeared legit as well. No comments about the movement itself. He admitted it may be a relica or worse... stolen considering the price he paid. Hmmm...

Here's my question. Are there any tell-tale clues you fine folks can give me to look for when spotting a fake. All the obvious signs seem legit such as 3 dot crown, laser etched crystal, exposed 3rd oring on the crown tube, etc. Any dial subtlties, etc. you can point me to would be appreciated. My curiosity has got me going on this one. I realize there's no such thing as an instant-expert course on spotting replicas but any tips would be helpful. Thanks in advance...