This was in the classic center email today... It gives chassis numbers that had the early mirror:
The side mirror fits the 190c, 190Dc, 200 (up to chassis 064074), 200D (up to chassis 358853), 220b, 220Sb, 220SEb (sedan, coupe and convertible), 230 (up to chassis 034216), 230S (up to chassis 049525), 250SE coupe and convertible (up to chassis 088724) and 300SE (sedan, coupe and convertible). Additionally, the mirror also fits the 230SL and 250SL (up to chassis 002979).