Krauss Stereoplast Stereo camera

Beautiful G.A. Krauss Stereoplast with two Tessar 5,5cm f4,5 lenses and a glass plate magazine, see photos for details.
The glass plate magazine is stacked with glass holders and plates but I cannot tell if they are all exposed or not. I definitely exposed the one on the front and a second one. High risk of all being exposed.

The shutter is functional and works accurate, the aperture can be set smoothly on both sides with the aperture slider, the viewfinder is not clear (it seems the mirror is pretty dirty).