35th Transportation Corps Service Group patch, World War 2

I have in my possession the shoulder patch from my Grandfather's unit in WW2, the 35th Transportation Corps Service Group. He served in the South Pacific, from Australia, to New Guinea.

I have looked up the unit and patch online and cannot find much, other than a mention on a site that Australian made versions are very rare.
http://www.usarmypatches.com/History%2035th%20Transportation.htm

I'm looking for any information on rarity.

Thank you