Shanta,

My understanding is that an "avantgarde" style grill is actually a copy of an SEC-style grill, used for 124, 123, 126 (sedans), 201's and others. With this in mind, I don't believe an (avantgarde) grill exists for the SEC.

You may search for a true SEC grill at a used parts center or you may have no alternative but buy a new one.

There may be some additional advice available from the SEC gurus at www.mbcoupes.com

Good luck!