Alfred,
The chrome plated washers in the black circle you drew go in between the star barrel and the grille surround frame. These act as adjustable spacers to achieve the alignment necessary to line up the chrome against the long ridge that runs from headlight to headlight(almost) on the painted surface. You can use one on top or two or three-depending on how much of an alignment you need. Some grilles have none, whilst others have one or several. Again it all depends on the alignment.
In your picture, you indicate the magenta asterisk (*) screws as for the ends of the wings, that is not correct. These two screws go to the top and bottom of the barrel, to screw into the barrel to hold the frame surround(these are the screws that hold the adjustment washers as noted above. But the nuts and washers next to them go to the ends of the wings with the small 8mm bolts indicated with the red asterisk (*).
Hope this helps. Also will help to put some black electrical tap between the grille surround and the painted metal surface to act as a cushion.
Walter
1967 220SL-diesel