I am at a loss as to why you need to remove any bolts, let alone the window frame ones, to swap the mirror.
I know you can do it without removing the door card because I have done it.
Removing the door card complicates the job because it's almost impossible to remove it without trashing the upper locating rail.
To start with I have not said about removing the door card; just taking the screws out around it's perimeter so you can just pull the card enough away from the door frame to easily access the bolts.
As far as the bolts go, on the three occasions I have changed my door mirrors on my 3.2, the last just one week ago, the mirror housing would not part from door before I had unbolted and removed them, with the screws needing to come out.
Maybe my late Omega is an exception, but this is what I have found on all the Omegas I have owned where this repair is required (5 times now)