V definitely Czech, Hermannshutte............
See the book and CDR, and particularly p 23 of the book.
Both Stoelzle and Inwald had head offices in Wien, but that does not make them Austrian, or by inference, German. In the light of subsequent Nazi actions towards both Jewish families, one should be very careful of how one classifies/refers to, this glass, and indeed, the families.
Certain family members are still seeking (70 years later) restitution of their assets, and particularly Stoelzle family businesses stolen by an Austrian bank, which is still active.