Interesting. I would think it would be difficult for a person or even a family to manufacture that amount of fake products and have them actually pass for the real thing.
At any rate, I checked my Fusions, and they have the serial numbers. Even though they weren't in the packages when I bought them.
Mine weren't in packages, either, but the Mach III logo is engraved on each cartridge holder (and they do have serial numbers). I agree, it would probably be difficult to manufacture counterfeit blades that looked real, but I suppose by the time you received them and realized they were fakes, it would be too late to do anything about it.