Canon EF 135mm F/2L USM Lens for Canon SLR Cameras - Fixed International Version (No warranty)

I've been buying Canon lenses for years. Both gray market versions and USA-warranty ones from great, reputable stores like B%26H and Crutchfield. This is the first time I received a supposedly new lens, and a gray market one at that, whose serial number on the box couldn't be read (as far as I could tell, the number was tampered with by the seller to be concealed), which means the lens' origin can't be verified. To make matters worse, the lens' metal mount has clearly been used before (it was slightly damaged) and therefore the lens is not new, as advertised by the seller. Based on my experience and after carefully inspecting the lens, this item was either returned by another customer, or was previously used as a demo lens somewhere. There's nothing wrong with the lens in that it focuses as it should and captures good images, FOR NOW, but since the lens' serial number/origin can't be determined and it's not in brand-new condition, I returned it immediately. Even on gray market products like this (that don't come with a USA warranty), you should still be able to match the serial number on the lens with the one on the box. When such is not the case, you know something is seriously wrong and you just bought a fake product, whose quality, performance, condition and durability are all in question. Buyer beware.