I contacted the State Library of Victoria about a year ago to see if they would be able to identify the V505 maker. In short, "no". They have a lead, but more like a needle in a haystack. An excerpt of their response is below...It’s seems the V505 is a jacket we don’t discuss much . Does anyone here own one? I’d really like to know more about the history and makers of this variation of A2 jacket.
Unfortunately I have been unable to connect any of the listed odes to any factory, product or tender that might suggest a manufacturer. Given the apparel is of a military nature it would most likely have been requisitioned or tendered out by the Commonwealth Government but the codes do not appear in any relevant context in the Commonwealth, Victorian or NSW government gazettes.
None of our reference works on Australian military uniforms give any indication of individual codes of any description.
I have no doubt there will be a list of relevant codes somewhere in the National Archives of Australia but how you would go about finding it is somewhat of a puzzle. It is not indexed (but relatively few such documents would be) individually and various searching doesn't reveal any blindingly obvious series of documents.
I originally understood the "V" to mean of Victoria state manufacture, but am no longer certain after seeing the State Library of Victoria response. At this point we don't know who made it, why it was made, how many were made or for whom it was made. There is, at least, one period picture of an American wearing one (above in post #172). The paper trail starts in Australia, but no one has started that path yet.
It possibly has a collar stand construction made of cowhide(?) using a khaki twill lining. I recall from an old post that Roughwear (Andrew) may own one, so hopefully he can add more.