12 years ago i owned a 81 320is that i have always regretted selling. Recently i bought a decent 79 320i to restore. When i was doing some reading i saw that the 320is came with a "dual operation sunroof". I know my previous 320is sunroof would pop up or slide back. Does this mean that the earlier car's sunroofs would only slide back? Was the "dual operation sunroof" an option on earlier cars? I'm only asking this question because i work out of town for months at a time and have no way to check.