I have attached a copy of an old Natis Certificate - how it used to work (and I'm sure still does) is that official importers are linked to the NATIS system. For every bike or ATV they sell, they register the VIN and engine as well as Model Code on NATIS, and NATIS then issues this document (we used to joke and call them Birth Certificates). The new owner then took this certificate to the Licensing department and with it, he or she got the Ownership papers and put the vehicle in their name.
Now in the case of most off-road, Enduro or Track bikes, the owners never needed papers, so they didn't bother to go to the Licensing department, so the NATIS system then archived that VIN number.
If you are really lucky and the bike has never been registered you can apply to unarchive the NATIS and then you can register as a new bike - which is why a lot of Track Bikes from 5 years ago are 2021 models!
But again, if that model code or vehicle register number has been loaded as "Non Road use" while you could get the bike legal to ride on the road, you will never be able to license it.
I know it's not ideal, because you already own the KX, but if you absolutely want a 2-stroke road legal bike and are a Kawasaki fan, look for one of the Road-legal KDX200's. They have lighting coils, so you won't have to stress about riding at night, have speedometers, and also oil pumps, so you don't have to worry about pre-mix.
Most important, they also have ignition and steering locks fitted so you can actually leave them parked somewhere.