The screw is p/n 42127-S8, the same as used on the grill ends and its lower attachment to the lower grill bar assembly. The head marking "CF" is occasionally reversed to read "FC". There is also a difference in the recess portion of the head design, early recesses are relatively flat, and later recesses have a slight upward slant to the "hex". As this particular part was use in all years for light trim attachment and grounds, many supplied were probably used, RBW, "D" and others.
Jim
I knew the bolt master would chime in at some point
Thanks for all the useful information Jim... this helps a lot...
Jason