s500, I think you're not in luck. The same part number of cover (210 811 01 60) and mirror (202 810 01 21) are common to the 96-up W140 and 96-99 W210. The 92-95 W140 uses a power folding mirror with a different housing. All according to the EPC anyway.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD