The confusing thing about the black paint below the bumper is that the spoiler was body colour and that all-but covered the black paint.

When you follow the tradition of the performance Holdens, GTS, GTR etc, the Sandman received the same treatment, so it stands to reason that the front should be black. However, in my opinion if you are fitting a spoiler and it doesn't completely cover the black paint and leaves a small amount of black showing, then I'd paint the front body colour just so it looks neater.

Depends on whether you are doing a totally perfect restoration, or are fixing the things that Holden didn't get absolutely right back in the good old days. It's a bit like putting the anti-intrusion boards on the back of the seats.... I wouldn't put them on because they look cheap and none of us are going to be carrying lengths of pipe any more, but to be totally authentic they need to be there.