You are going to remove most of the top rivets anyway, so you will only have to remove the bottom row to have all the rivets out, and by removal you don't have to worry about trimming the skin to an exact fit right off the bat. The skin you want to replace sides in under the window frame. The sides of the frame are held on with a dovetailed slide that needs to be driven either up or down to remove. Do these first. This will also allow you to reseal the front window which has a tendency to leak.
The new skin should polish up the same as the old.