I think 327 Cabriolet's and 327 Sport-Kabriolett's should be merged as Sport-Kabriolett's. Seems like it's the same thing, they were all 327 "Sport" Coupe's or Kabriolett's no matter what their spec. Also in the period material Kabriolett is used.. see https://ibb.co/JrK770f

http://www.imcdb.org/vehicles.php?make=BMW&model=327+Cabriolet&modelMatch=1&modelInclModel=- on
http://www.imcdb.org/vehicles.php?make=BMW&model=327+Sport-Kabriolett&modelMatch=1&modelInclModel=on