John,
I lived in Asia almost 20 years. These people are masters of duplication and we Westerners can be so gullible, comparatively.
Ex&le: In the late 70s I was headed back to the states and wanted to pick up a new model Nikon (can't remember the exact model). I had friends who had a contact in Kowloon, HK who would, if you told him who you were and mentioned who you represented, would sell you the desired product for the "real" price, no bargaining needed.
The morning I got there, I headed up the street, looking in all the shops to compare prices, so as to be ready when I arrived at my destination. I introduced myself, said the message I was instructed to give, and mentioned the Nikon model I wanted to purchase. Whereupon, the store owner (a seasoned old Hong Kong Chinese merchant) informed me that they were all out of stock, in fact everyone was out.
I mentioned that I had seen a few in store fronts on the way here, to which he replied, "they're all the fake ones, you want one of them, go buy it." I purchased a different camera and left.
Another ex&le: I have a Chinese businessman friend who is a watch dealer in Thailand. He does all my work for free because I once wrote him a nice letter of reference so that he could get a tourist visa to the states. He showed me his line of Seiko watches saying: "This one is real and from Japan, this one is made in Hong Kong, this one in ... etc., etc."
I have also seen knock off Rolexes so perfect that there are absolutely no blemishes or rough spots, even if viewed under a 30 power loupe. They have various grades, A, B, C, etc., all fakes.
So, go figure, but don't buy that lens if you know what is good for you.
Best Regards,
Ron Myers
San Diego