Tony,
That a question that the Qld club should best answer, but I can tell you that at every Nationals our club has organised, we have had a number of non-vehicle entrants: club members who are participating without cars. I've been one myself!
And then of course there are the entrants whose cars aren't quite finished, or fail to proceed at the last minute and decide (good on them, too
) to come along anyway in their other wheels.
So I would be inclined to enter with the official entry form (so you get all the various goodies). Because it's a club event, we support all club members who want to participate, whether they can bring a car or not. After all, it's the social aspects that make the Nationals such a great weekend as much as the cars on display.
More power to you for wanting to be part of it.
Hope that helps,
RET