Our W123 300TD we owned prior to our W124 300TE had "clear" (ie. not yellow) fog lights. In fact, all MBs in Oz have white fogs. I believe the yellow colour is either the bulb itself or a coloured cover that goes over it. Then again, your yellow ones may be the lenses, given that the US models got different headlights altogether. Our W123 had circular shaped reflectors behind a one piece glass cover that had the fluted lenses moulded into it.
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.