So, the camera arrived. Unfortunately, even though the Tessar was described as "semi-auto", it is preset. This alone would be ok I guess, even though I would have preferred the semi-auto version, but the camera is as well the FX without any aperature stop-down thing (this version:
http://www.praktina.com/pucam04.htm ), which means I could not use any semi-auto lenses on it. Since the ebay ad said it's a semi-auto lens and those work only on the FX with the semi-auto feature, I assumed it is one of those. Of course I could have asked. The camera mount internals where not shown on the photos, so the only glue would have been the lens. And of course, the FX versions with semi-auto aperature are much more common then the preset only ones.
I contacted the seller, a repair man in Slovakia who knows about cameras and not just a random person selling a camera unknown to him. His answer: Sorry, I copied the text from an earlier ad (but updated serial numbers), but you should have seen in the images that it's preset and not semi-auto since it looks different.
I meanwhile found as well a IIa with double aperture function (SB and ASB), in a good shape (have not received it yet, but seller seems to know what he talked about and used it not too long ago, without shutter time problems or light leaks). It comes with the Pancolar 50/2, Flektogon 35/2.8 ASB, and Sonnar 135/4 (plus a few other things, like both prism and waistlevel finder, rapid-winding lever, some original boxes and papers and stuff).
So, what do you think about the FX? I mean it is serviced, works well, outer appearance ok without being crazy mint, but limited to preset/manual aperture lenses. Should I keep it (if yes, why?), or use the ebay return due to wrong item description?