I think I might have found some of the answer. Looks like the Americans had their own Disposals Commissioner running around the islands selling gear to all comers.
A lot of mention of stuff being bought by Australians (Leslie Theiss and his brother were quite clear in their histories that they bought thousands of tons of equipment - earthmoving and vehicles- from the Americans in the islands, not CDC)
Looks like there was a second commercial stream of ex-military equipment flowing into civilian hands in Australia.
https://books.google.com.au/books?id...201946&f=false