Josef Ritter might have been "somewhere close to Jani" by US standars, but rather far away by Central European standards smile
I was in western Czechia recently (near Plzen) but Ostrava is in the oposite, eastern part of the Czech Republic, near the Polish border; I was never in those parts. The gun in question might also be of Weipert/Vejprty or German or Belgian origin so touchmarks are a must.

With kind regards,
Jani