I've even seen a Zorki engraved as a Foca PF2, does'nt even look vaguely the same.
But some people still buy them. Old story "if it looks too good to be true, then it IS too good to be true "
We had a guy aproach our camera club for a valuation of a Leica LUXUS, there are three very experienced Leica collectors there, but when it was explained thoroughly why it was a fake, he called them all the idiots under the sun. A solicitor in the club warned him that if he now sold it as a "LUXUS" after being given this info, he could be prosecuted. The club then got a letter from his solicitor, however after it was explained to him he advised his client to accept he had been "done" and learn the lesson.