If you want to paint the mirrors, you will need to scuff up or lightly sand the chrome for best results. Steel wool, Scotchbright pad or fine grit sandpaper, (200 or finer), so that the new paint will have the ability to stick to the chrome. If you plastidip, don't bother to scuff them up, just clean well. That way if you remove it later you will still have nice chrome. You'll want to scuff up or lightly sand the grab handles as well prior to painting.
Considering the range of pretty cheap mirrors available, I'd suggest you just try to find a set you like in black and see how that goes first. Unless you are thinking about doing a color match to the bike or some fun with contrasting colors.
Cleaning, scuffing/sanding and careful masking go a long way in getting good results in the end. Probably some Youtube videos on prep and paint how to's that you could watch before you start too. Do remove the mirrors from the bike to do the work. Don't forget Yamaha likes to put a right hand thread on one side and left hand thread on the other side so the wind can't blow them loose.