Aero mirror upgrade

I have an '81 Malibu with the standard single chrome outside mirror on the driver's door. I'd like to upgrade to the later Monte Carlo "aero" style outside mirrors on both doors. I know that these mirrors were available on the '86 & '87 El Caminos. Is there a mirror gasket (black plastic piece that goes between the mirror and the door skin) that is specific to the Malibu & El Camino door skin profile, or is it the same gasket that is used on the Monte Carlo? Also, is there some kind of mounting template available that will allow me to correctly position the mirrors on the doors? I know that they're positioned further forward and higher up on the doors, close to the door glass at the front of the doors. Thanks in advance for your help.