M, in case it's useful, the book on Czech Toilet Glass, Shranky Vuni, by Jitka Lnenickova & Petr Novy, gives the following as some of the producers of oroplastic decoration:
W Kralik in Lenora,
Moser in Karlovy Vary,
Harrach in Novy Svet,
C Goldberg in Novy Bor