Sorry you got a fake, so now you need to educate yourself on what's real vs. not so it won't happen again.
Read magazines. Go online to the better places like Roger's Knife Works to get an idea about what you're looking for. Go to the Benchmade Forum and even better yet to Benchmade's main site which has virtually every model catalogued or is at least close to that.
These fakes like the one you have are flooding the market, some are better than others and are hard to tell between the originals, and here's where knowing what to look for will save (and COULD save) both your fingers and hard-earned money.
Good luck out there.