Luiz,
the bellows is quite large to be the macro bellows for Zenit (PZF I think, no? PDF is the periscope I thought). Aren't those much smaller though, about 5x5cm bellows? This unit is quite large - maybe 12x12cm bellows... I can measure it exactly if you're interested. Also you think this is only a front plate from Zeiss Ikon and not some kind of mechanical hybrid? I can take off the shutter take it up and compare at some point too... very weird camera, that's why I got it...

.. The frankensteins like this is my passion

.
Vlad