That's my understanding. I've only seen one, and that was decades ago. Wikipedia says they were a completely Austrailian design, but I thought sure I had read that they were a-body based.
There was a great write up in a recent issue of an Australian magazine about the Charger's beginnings and development, which also interviews with a couple of those that were there during the initial stages. I'll see if I can dig it up and get some scans.
One thing I found funny in the article: They initially considered developing a right-hand drive US Charger or Challenger, but decided it was too big for the Australian market - so the Oz Charger was born. The Charger was approx 11"s shorter, and 2"s narrower.