As mentioned, the standard W124 wheel is a 6.5 x 15 ET49 (or ET48). Sportlines came with a 7 x 15 ET41. The similar looking wheels on a late W126 or 107 are a 7 x 15 ET25 and those on a 190E are 6 x 15 ET49 except for the Sportline which runs 7 x 15 ET44. As you see, many similar wheels but with differing widths and offsets, and these are only the 15 hole wheels (the later 8 hole differed slightly again). The one thing that is common to all is the threaded length of the bolts for all these wheels is the same. The length of the bolt heads vary though, to suit the different wheel offsets. Aftermarket (rather than OEM) alloy wheels also often have different bolt lengths and of course steel wheels require different bolts.
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.