Actually it is wider than the Mk3 tray.
However upon reviewing the NSW Regs, the width is measured across the body or in this case the tray. The body is just narrower than 2.5M with the clearance lamps protruding past the 2.5M with which is permissable.
The 60mm overwidth (30mm on each side) is the hub caps and wheel nuts and the regulations allow hub devices to protrude past the 2.5M width, up to IIRC 150mm.

