Most fakes online are fairly easy to detect, shotty stitching, generic box tags, etc. The higher the value of sneaker the farther the bootleggers will go to knock someone for their money. Here is an updated guide of things to look for with the Tiffany SB Dunk. Thanks to chip_SB for putting this together.
The ankle collar portion of the shoe (the small area separated by the the swoosh and dunk flap, the leather is really cheap, and has a different feel to it compared to a legit counterpart.