[xb-60]

Thanks Larry. I see the logic. Safe to conclude from the pictures of CSX2433 that there are two panels used on this car?

Incidentally, I checked the pictures I have of CSX2345 and all but two pictures show CSX2345 with no strut (forward or rear) bracing on its roll-over bar! That would be unusual, and strange, as it can't be as strong as a braced bar.
In the '64 Targa Florio with Bob Bondurant at the wheel, it had a forward braced bar. That's just by-the-way....nothing to do with original question.

So should I assume that exposed vertical legs would be the norm on an FIA roll-over bar?

Cheers,
Glen