https://infrastructure.gov.au/roads/motor/design/adr_online.aspx
The Italians probably just welded on a plate and said you deal with it. Although it could have been Frasers.
Mine is 12/89 and a 17 digit, Frasers obviously got their act together by then. As long as your frame number and compliance plate match it’s legal. Engine numbers are another kettle of fish, Faloon’s book is a stab in the dark. It’s all to do with what the hell have we got to stick in these frames. You have to remember the factory went belly up in 86. New management and systems were being initiated and they had to sell bikes. Production control we have in place was their aim, not necessarily the way things were.