I took one of these apart once off a 72 Cutlass. I carefully marked and pried open the control end portion of the cables from there crimped positions. I was able to free the cables and slide the entire operation apart. There were 2 heavy duty phillips head screws from up underneath holding all that crap together. Everything slid apart and was able to paint the junk separately, and didn't tear anything up. Gotta be careful with that control end piece. It's potmetal type crap and will bust on you in a heartbeat if not careful. That was like 30 years ago, so I don't even remember how in the f** I got it together again. IIRC, I used a pointed punch to dink over the crimps again to keep it all together again. Total PITA and I wouldn't do that again and the next time I had to deal with it, I just had the painters tape around the mirror section and do the best they could.
Not sure if this will help any.