Not so much a fake, more a 'bitza'. As darkosaric suggests, someone had a Contax III with a faulty meter and faulty shutter, and decided to make it into a usable camera with the help of a Kiev 4.
Front plate: genuine. Anyone capable of doing such a good job of taking off the Kiev logo, engraving Contax, and re-plating, would have made a MUCH better job of faking the rest!
Meter and top-plate: obviously Kiev.
Top-casting: almost certainly Kiev - probably necessary with the Kiev meter. The top covering looks Kiev-like, not Contax leather.
Back: definitely genuine, for too many reasons to list.
Body: almost certainly genuine. There is no evidence of the Kiev 4 flash connection on the inside, so it would have to be Contax, Kiev II or Kiev III. Contax is much more likely.
Shutter: almost certainly Kiev. The sprocket spindle appears to be black. Every Contax that I have seen has an aluminium-coloured sprocket spindle. Whoever did the swap put the Contax focus wheel on the Kiev shutter (there's a slot down the middle on the milled edge).
All the seller's current items, and all the completed listings I can see, are photographic, so he ought to know what he is selling, but many quite big sellers seem surprisingly ignorant, and presumably don't have time to research everything online.