Are the Yulunga games played in their traditional form?

Not always. The introduction says:

• Some games can be played in their traditional form or close to it, sometimes using modern equipment.
• Some have been modified from their traditional form so that players understand the basic skills and game play while considering safety and ease of play.
• Some have been reconstructed from vague or incomplete accounts into what is believed to be an accurate representation.

The book is based on several hundred accounts collected from all parts of Australia and the Torres Strait Islands, many recorded in the nineteenth century by explorers, government officials, settlers, scientists and missionaries. It notes there are comparatively few descriptions by Indigenous people, though efforts were made to include a significant level of Indigenous input.

Source: Yulunga: Traditional Indigenous Games (Australian Sports Commission, 2008), Introduction.