It was mentioned by the Minster at the time. Sounded like spin considering the SH would be itself being replaced in the USN by JSF. Even if the USN did buy them back who would they sell them to? There are no other SH operators.
Some reports as recently as last year of a sell-back-
Australia Unruffled By F-35 Delays - Defense News
Nelson's statement-
US fighter to fill air defence gap - National - theage.com.au
Super Hornet will be around for a long time in RAAF service.