On my 200 that area is an extremely tight gap, and the grille has tabs that snap into slots in the bumper cover. Did they just force it in there? Trim the tabs and slots to fit?
Looks like the tab was trimmed / replaced with a screw but I dont see evidence of trimming on the grill, so will assume they went with force. I'm pretty detail oriented and there's no bulge or unsightly uneven surface as a result... just did a wiggle test on grill, bumper, etc and not seeing any movement.
To be fair, I told them the could drill straight into the bumper if it was easier... I'm not too attached to my bumper and it's got a few love marks on her already