Just a couple of quick observations of the ZF. The case shape looks decent with correct flat bottoms on the lugs as oppose to pointed lugs on the 127 or KW 617. The gen appears to have more of a satin reflective surface.
The "1950" on the crown guard lever is in a different font compared to gen.
The "12" "3" "6" "9" on the dial have a slightly different shape than gen. They have the same shape as the numbers on a 127 dial, but should be more like those found on more modern Pams like the 504 dial for example. Gen on bottom
With KW on top, ZF on bottom you can see the differences in lever shape and lack of chamfering on the ZF's crown guard.