All right. I bit the bullet and decided to go for it. I started with the intention of priming and painting it flat black but after I started I was happy with the results I was getting sanding so I stuck with it. I was also afraid flat black paint would scuff really easy vs just leaving it as plastic. I'm hoping we will not have to "maintain" this finish over time by re-sanding.
I did pop out the lens cover. It does snap back into place fairly well and is held very securly once you put the back cover back on. If it becomes an issue I'll hit it with some super glue but I don't foresee needing to do that.
I sanded the entire thing with 600 grit until I was happy with the results. I worked in a north/south direction as much as I could mostly because I went the other way a few times and it took forever to get rid of the sanding marks so I stuck with how I started. Maybe circles would work better, I'm not sure since I've only ever sanded something to get old paint off to repaint. I've never tried to make a nice finish using sandpaper before. I think it turned out great and looks uniform so I don't want to mess with it.
When I was happy with how the 600 grit turned out I decided to finish it off with 2000 grit. The 2000 grit gets rid of the sandpaper marks from the 600 really nice. The cover feels almost like the back of my EVO Shift used to feel with that sort of soft touch plastic. Wouldn't surprise me if that stuff is made using ultra high grit, uniform sanding somehow.
The color obviously isn't exact to the rest of the back but it is much better than glossy. I spent the better part of the evening working on it off and on. If I got annoyed or in a hurry I would set it down and do something else, LOL. I didn't want to rush it.
Let me tell you, it is a weird feeling the moment you are about to hit that cover with sand paper when you don't have a spare... Once you get going though it's not so bad, especially when you start seeing results. I just kept at it until I could no longer see any glossy area under a bright light.