I have a fondness for dog buttons, but not this type!
Pariah dogs are wild dogs. Proti is a barren Greek Island. However, I cannot confirm the veracity of this story.
An explanation for ‘unoffical’ buttons and badges.
The 2nd, AIF was the name given to the volunteer personnel of the Australian Army raised from 15th September 1939 by Robert Menzies. The initial rush of enlistments must have out-paced production of requirements. See http://www.austbuttonhistory.com/trench-sweetheart-art-and-miscellany/#Unofficial_Uniform_Buttons