The report on the cars seen at Anstead....yep only mentions parkers....there's no mention in media of missing number plates.
Wed May 16 2012
A witness has told police they saw two four-wheel-drives near where Allison Baden-Clay's body was found, on the same morning that her husband reported her missing.
The witness allegedly saw a white four-wheel-drive that had its headlights switched off, and only parking lights on, that was closely tailing a small blue four-wheel-drive near Kholo Creek crossing in west Brisbane, at around 4am (AEDT) on April 20, the Courier Mail reports.
The cars were allegedly spotted at Anstead, within 2km of where Mrs Baden-Clay's body was found 10 days later
http://news.ninemsn.com.au/national/8468149/witness-comes-forward-in-baden-clay-case