I can send you some compliance plates if you have a problem. They are from a parts car I bought off a teachers family. Quite legit. They are from a '71 4door sedan.
The rego people definitely don't check body numbers against plate serial numbers. If the body is stolen, then you might want to bog over the numbers on the firewall, and punch the numbers from a known good car on the shock tower. I'm happy that my project car, which was bought as a shell, came with matching number compliance plates.

I know in NSW, if it's an old (30+ years) car they just write "pre-compliance". The Datsun theft market would have been much worse in the early 70s if people had known it would have been this easy to register stolen old cars today.

I don't condone car theft, I believe car thieves should be forced to eat an entire Volvo (slowly, in very small pieces) if they get caught stealing cars.

Chris