I can't speak for all of them, but the light setup on my R107 is very different from the W126. It uses no "light pipe" and instead uses a very long lamp holder with the tiny "grain of rice" style bulb fitted. Unlike the 123/126 setup, it provides more than adequate light with the stock setup with the rheostat bypassed.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)