yep, I think I remember using a flathead screwdriver and prying the two metal pieces apart, if you tug on the mirror you might pop it loose. Be careful because if your car is like mine there is all kinds of electronics in there for the alarm and auto-dimming, the 129 was adjusted manually, but the 140 was electrically adjusted and had motors in it. I don't know why MB did this, it was kind of strange, but those darned mirrors are always goofed up, every 129 I test drove while looking for one had the same problem. Good luck and have a great day!
Regards,
Brian