These flats are part of a series of seven pices from Scheibert called „Polen 1935“ and „Kavallerieparade for Marschall Pilsudski“. This is an information from a german Book „Scheibert/Schiller: Geschichte einer Altwiener Zinnfiguren-Offizin“ at page 35/36.
I don‘t know about the owner of the moulds at this time.
Best regards, Henry