Tim, sorry to say, but this Donald Gunn was wrong, or Pitt Rivers (where much stuff is wrong labeled). Gunn collected at Bor. A little town where you can't find only one Shilluk, they are more north. Bor is Dinka region.
https://en.wikipedia.org/wiki/Shilluk_people
Capital town of the Shilluk Fashoda is right, it's today Kodok north from Malakal.
Here akso a good ethnic map
http://mapeastafrica.com/wp-content/...UDYAREAETH.jpg .
Last not least a Dinka warrior in more modern times, but with his old club.
https://www.flickr.com/photos/32977742@N08/3178521767