Personally I'm not convinced, and judging by the comments on the two blogs not many other people are either. This looks a lot like an off the shelf Samsung handset, not something I'd expect from Apple. Surely if they really are going the MVNO route they'll ship their own hardware, if only to differentiate themselves from the other networks? I mean, if they don't ship their own hardware what's the point, for Apple, of doing it in the first place?
People have also mentioned that the SIM looks a lot like a cut up iTunes gift card, but to be honest I don't think that's not such a strong argument, after all it just means that its carrying the same branding as another of Apple's products and one which is closely related to the phone. Surely any Apple phone would ship with iTunes? However the argument that the SIM should have an identity number on it is bogus, those numbers are usually printed on the same side of the SIM as the chip contacts, the number wouldn't be visible in this picture.
That said, this is pretty much has to be yet another in a long line of distinguished Apple fakes. I've talked about this before, the hardware margins in the mobile phone industry are vanishingly thin and Apple is used to much larger profits per unit. Move along, nothing to see here...
Update: Apparently nobody was ever claiming that this was Apple hardware, and it was only the SIM card that was supposedly an Apple product. In which case, what's it doing inside that Samsung phone?