First off would be the Hogue wrap around rubber grips. I detest them. They are fat, sticky, and they do nothing to help me control the gun. What would I screw on? Wood or rubber double diamonds. The down turned "duck bill" grip safety would have to go. I would either install an Ed Brown grip safety with the speed bump removed, or I would go with a smoothed out GI style grip safety.
The rear sight would be the next thing punched off this gun. A Commander is a carry gun. Carry guns deserve a fixed rear sight. If I could get a Ted Yost Retro rear sight, that would be my first choice. If not, something similar. Finally, it would get a long trigger and a trigger job. My preference is a flat mainspring housing and a long trigger.
So for those who have asked, that is how I would immediately alter this particular pistol if I purchased it. Oh, one other thing. I would check the chamber, and place the the thumb safety in the up position.