This unidentified mark belonged to a retailer or decoration studio as the items in question all came with original manufacturer marks by Jaeger & Co. (Marktredwitz), Mitterteich AG (Mitterteich), or Gebrüder Winterling (Windisch-Eschenbach).
Marks
M170807a
Crowned square containing a jug or vase above "BAVARIA".
M170807b
Crowned square containing a jug or vase; no country of origin.