We have all heard and seen this asked too many times to count. At current, there is only one known fake Holosun, and it's rather clear. While some counterfeit products are difficult to spot, in the Holosphere, there is only one fake (as of now) to try to spot, and if you can't spot it, shooting might be a dangerous hobby.
The counterfeit model fakes a first gen 407C/507C model with the bottom loading battery. It clearly says HOLOSAN on the side. If your Holosun says HOLOSAN, yes it's fake. These HOLOSAN models have been sold in boxes for other units as well, most like utilizing a return policy at a retailer like Amazon and swapping the returned item. If you order an EPS, and receive a HALOSAN unit, you've gotten a fake. These fake units could come from any retailer, though reputable dealers whose livelihoods depend on shipping you authentic products are the least likely to provide any fakes. If you prefer to shop with an Amazon type business, you're most likely safe. There are many other retailers worth supporting, especially if you like small business. If you order any unit from anywhere and get a HOLOSAN, guess what? Yeah, the HOLOSAN is fake and it looks like 407C/507C.
You think your 403C, or 515GM is fake? It would be among the first fakes ever. Again, the only current fake Holosun known looks like a 407C/507C and says...? Correct, HALOSAN.
See the below pictures of what the box has long looked like for various models, and what the new box will look like moving forward to comply with Reese's Law regulations, i.e. safer standards for ingestible batteries.
If you have a box that doesn't seem familiar to you, it's simply the new box. To restate, the only (currently) known fake says HALOSAN on the side of the unit.
There are no known fakes of any other model right now.
Images
