I had a buddy who bought some Callaway irons on E-Bay, and liked them. He took them with him to Asia on business, and upon reentering this country, they were taken by a customs official. The customs official showed him, through manufacturers markings, that they were counterfeits. Then, the clubs were confiscated, since my friend could not prove he didn't buy them in Asia, and destroyed. He says there is a huge market in Asia where you can buy these clubs that look exactly the same, but are clones. As a result, I'm sure that they make it in to our country, and are sold on E-Bay.
When I recently bought my Mizuno irons, I took the E-Bay median price to my local shop, and they matched it. I'd try this first.