Yea, isn't that bizarre? But where does the tapping screw come into play? With your photograph, Mark, there is no way to screw on the nut because the pins for the grill vents go into the vent duct and there is no way to put the nuts on!!! I broke the grill pins when I took them apart to paint 26 twelve years ago, and I broke them again this time. There is just no way to get to the back of the grill pins. Perhaps the C clip only clips to the vent duct plate, but one would have to tear the vent duct off to get to the pins. I tell ya, I hate them C clips. Ruined another perfectly good set of grills. With the tapping screw shown in the fiche, the grill would have the screw head exposed. Not a bad detail, but I don't recall ever seeing it. There is no supeceded part number for the grills in my fiche, making me believe they were always this way.:dead: