Originality?
Since the washers to act as spacers between the flange on the shroud and the rivnuts are not listed on the parts page, I suspect that adding these washers was not something done at the factory, but by owners seeing the gap between the two. Maybe the "springiness" of the flange when the screws are tightened provides enough tension on the screws to keep them from vibrating loose, since there is no lock washers involved with the screws.