Engine cover holders (gromets/plugs) - E420
 

On my 1997 E-420 the engine cover has two rubber holders (gromets) in the front that slide over two posts on the engine. The rear of the engine cover has two holes for securing screws.

The two rubber holders in the front have worn out and broken off. I went to the Mercedes dealer today to get replacements, but was told that the holders are part of the engine cover and that I would have to replace the whole cover including the part that goes over the air filter.

I am wondering if others have had a similar problem and where they got the replacement rubber holders (gromets), because Mercedes does not sell them.