Few photos do show a roof aerial, but it could of been put on, it's not a hard job to do.. the fact it has half coloured bumpers and no black trims, archs, sill covers tells me works been done to it... weird it has that little arch slat on the back?
Do the G40 tailgates have 2 holes for the rear badge for the 'g40' bit?
Hard to prove otherwise though really.