I don’t know how to check whether the Winnetou BDs are really region-free. I can’t play Blu-rays on my computer, and my DVD-BD player doesn’t give me that information (or I’m too stupid to figure out how to get it). On the back covers of the four Blu-ray box sets that I have, the following specifications are given:
Karl May Collection I
Der Schatz im Silbersee, Winnetou und das Halbblut Apanatschi, Winnetou und sein Freund Old Firehand
Region codes: A, B, C
Audio: German and English
Karl May Collection II
Unter Geiern, Der Ölprinz, Old Surehand 1. Teil
Region codes: A, B, C
Audio: German and English
Karl May Winnetou I–III
Winnetou 1. Teil, Winnetou 2. Teil, Winnetou 3. Teil
Region codes: A, B, C
Audio: German and English
Karl May Shatterhand Box
Old Shatterhand, Winnetou und Shatterhand im Tal der Toten
Region code: B
Audio: only German