These were removed from my G Wagen around 10 years ago. I have three of these arches, one rear and both front. They are made of a rubberised material, likely OEM.
DRYER AIR CONDITIONING FITS: MERCEDES-BENZ G-CLASS G 300 CDI .MERCEDES-BENZ C
CONTROL UNIT GLOW TIME FITS: MERCEDES-BENZ G-CLASS G 280 CDI /G 300 CDI .MERC
RELAY GLOW PLUG SYSTEM FITS: MERCEDES-BENZ G-CLASS G 280 CDI /G 300 CDI .MERC
CONTROL UNIT LIGHTS FITS: MERCEDES-BENZ G-CLASS G 280 CDI /G 300 CDI .MERCEDE