It is pretty easy to tell in person. Obviously someone could post real pictures and then send off fakes…but the second you got the fake, you would know.
The real ones have an inlay to them where the fake (the ones I have) do not..they are just printed on the ceramic chip.
If you are buying from eBay, just make sure they are legit sellers with lots of feedback and when you get them, make sure they are real. If not, report them and get your money back.