Any idea about the purpose that these little clips serve....the ones above the phone?

The 4 clips on the inside of the vertical cover appear designed documents of different heights.

Is the glove box on the American model (with 6 CD changer) much smaller that this?

 

looks like for calling cards.

 

That is a pretty good guess. I'll have to try to fit some name cards into the space. It is sort of logical that name cards could be tucked into the place just above the phone.

 

I just tried it with name cards (calling cards). Nope....doesn't work. I think it might have something to do with the phone. In 2005 MB went with a new phone for the SLK.