The OEM pads have a special metallized portion, the whole pad isn't metallized. Don't know if it makes a difference.
Last I knew, you could still get MB OEM pads for diesels... I got one when I tried to order a pad for my 300E... apparently they don't make the gas version separately any more.
I didn't like that metallized thing so I swapped mine for an aftermarket gas pad which has worked fine.
I used 3M Super Trim adhesive to attach. Over a year so far, no sagging or problems.
A previous thread with photos
Phil at PartsShop can take care of you.