The interior of my 1973 w114 280 looked pristine... except the gash in the speaker cover.
I grabbed 1 yard of black vinyl from this place ( https://www.perfectfit.com/product.aspx?d_id=15989&p_id=167820 ), traced the opening in the metal that's hiding under the vinyl/plastic original cover to know where to punch the holes, punched the holes, added black grommets and reupholstered using a thin black felth to put some space between metal grommets and the metal cover. Use E6000 glue as it's stronger then contact cement to wrap the vinyl around the edges.