I was just at a friends body shop looking at prices for different parts on the W140 and looked into this debate over the antenae's funtion. It's not quite clear were the AM antenae is located (the rear glass ($900) does not specify if it is included). The FM antenae for 92-95 was in the back bumper. From 96-99 this antenae was used for the cell phone and the mast on the rear quarter panel was for FM.
If I remember correctly, the book listed the cost of the antenae at $326. Just the mast and cable was $50-100.
Speaking of prices, the leather shift knob in a 320, 420 or 500 was $126. Guess how much the 600 shift knob was......$436. $310 extra for the shift knob to have a little wood and a V12 emblem, unbelievable.
All the above info was for the Sedan, I would assume the Coupe is the same.