No, I pretty sure you have to be out of the country yourself for 12 months as well.
Pretty much.
The intent of the rule is to allow you to import a vehicle that you purchased for use while OS.
The enforcement of the rule (distinct from the exact wording) is to ensure that you have actually used it regularly while in the other country.
I doubt that 12 months of ownership and four weeks of actual usage would be enough, but maybe 2-years of ownership and ten weeks of actual usage would be??
-----
My knowledge is old and my memory foggy (and should be taken with a grain of salt) but on the pre-89 stuff:
Pre-89 is easier because the cars/bikes are considered too old to be regularly used - they're supposed to be collector and/or special interest vehicles, basically.
Post-89, only cars (and I assume bikes) that are markedly different to those imported through mainstream channels can be imported as SIVS (or whatever they're calling it this week).
This is how R33/34 Skylines are allowed to be imported, but the Toyota Altezza was blocked because it was too similar to a Lexus IS200 (they're the same basic car, but the Altezza has the much better 4-cylinder motor, rather than the Lexus' I6).
A mate was looking at importing a manual Volvo V90 (a very rare car here, none were manual), but he was almost certain to be refused for being too similar to the Auto 960 wagons that came in through Volvo Australia.
Nissan took several months to import the S15 Silvia/200SX, so plenty of importers were importing them before Nissan Australia got around to it - once there were "official" imports, the grey imports were stopped.
All of this makes me think that the KTM990 is going to be knocked back as a SIVS vehicle.