yeh should have a philips head screw in the bottom of the upside down triangle looking piece that is on the door itself. Take it out, and then the cover will come out at the bottom (to clear the tab the screw goes into), and then slide up the shaft that the mirror itself is on. Be careful, the edges of that cover are kinda sharp and will slice you open if your not careful.
Oh and you will see 1 or 2 other bolt heads (besides the 3 that hold it to the door), those adjust the tension on the mirror head. So if your new ones move in while driivng down the interstate (mine did) you tighten those 1 or two up a little and it will hold the mirror in place more securely.