Pluto's "Bourf! Bourf!" in WDC&S 330 echoes the Hounds in their untiled Hounds and the Hare story in The Fox and the Crow 83 (Dec-Jan/64). Goofy echoes so many Fox and Crow (as well as Hound and Hare etc.) stories' "Ooo-hoo-hoo" in #358. (The Crow says it on the first page of F&C 83.) Note the nonstandard hyphenization of "Hoo-Doo" both here and in the Scooby Doo story "The Fiery Hoo-Doo."
There are a number of serials later in this run, setting aside these and Carl Fallberg's, that I can assign to one writing style, but can't be sure enough to say it's that of Beard & Harper. Maybe more on their style from other features will merge my two lists of writers' data and I can credit those stories to them in the future.
Beard & Harper Mickey Mouse serial scripts
in Walt Disney's Comics & Stories
|Oct/66 to Jan/67||#313-316||The Treasure of Oomba Loomba|
|Feb/ to Apr/67||#317-319||The Red Wasp Mystery|
|May/ to Jul/67||#320-322||Lair of the Zoomby|
|Aug/ to Nov/67||#323-326||Trapped in Time|
|Dec/67 to Feb/68||#327-329||The Mystery of the Wiki-Waki Wot-Not|
|Mar/ to May/68||#330-332||The Mystery of the Dazzling Hoo-Doo|
|Dec/68 to Feb/69||#339-341||The Strange Case of Professor Zero|
|Dec/69 to Feb/70||#351-353||The Sorcerer of Donnybrook Castle|
|Mar/ to May/70||#354-356||Chief Bigfoot and the Ghost Warriors|
|Jun/ to Aug/70||#357-359||Journey to No-No Land|
|Sep/ to Nov/70||#360-362||The Sign of the Scorpion|
|May/ to Jul/73||#392-394||Flight of the Dragon|