If you Google "fake Gamakatsu hooks" you will see a number of posts/reports of knock-offs being sold on-line. It seems the fake ones have steel that has a lower carbon content (more likely to snap or bend) and aren't chemically sharpened...Gamakatsu has a proprietary process (try the fingernail test).
Personally, for all the $$$ I spend to get out fishing....boats, gas, gear, etc...the last place I would want to save a few pennies is the business end of your tackle. After all, hooking fish and keeping them pinned is the primary objective in fishing. In the grand scheme of things, even the best hooks are relatively cheap.