.../... two large screws.../.... There are also two thick chrome spacers.../...
Large screws well ok... they are M5
The 2mm thick chromed washers are available to be fitted "as needed" between frame and barrel (no washers is to be preferred). This is to even out any gap caused by varying measurements (after welding etc.) for the opening in the front of the W113 body.
When working on the front of the cars body, it is vital that the edges of the opening in the front are shaped well, to make the chromed frame fit snugly and look right. If you re-chrome the frame, you may want to shape it to fit to the body, before handing frame over to chrome vendor.
Any misalignment is usually visible in the top, outer corners of the grille frame vs the body...
/Hans in Sweden