I commissioned an artist for £600 to make this concept art for what it might look like
The main optic in the middle with a top optic above and a canted optic to the side
The optic you have selected would be white and the other two optics would be grey
If you don't have either a top optic or canted optic equipped then those icons will just stay greyed out.
It's best to always show all 3 as one icon because it would be almost impossible to make an individual icon for the top optic attachment that doesn't just look like a main optic slot red dot sight, so some people would get confused which optic they have selected