Not sure what you are trying to accomplish.
I didn't like the amount of light that the sunlight let into the bedroom of our 5th wheel.
It looked like to much work to replace the skylight with all the sealant they used around it.
I sanded the exterior side of the skylight and used Rust-Oleum plastic primer and white paint to reduce the amount of light it let in.
The exterior shell of your skylight is probably a sealed hail shield, the interior should drop away once unscrewed from the ceiling. Once that is done you can A: paint it or if you prefer a less permanent fix B: put aluminum foil over it.
We opted for plan B when we bought our new rig a few years ago. There was way too much light coming in through the shower skylight. Removing the exterior hail shield and replacing it with a tinted one sounds like a lot of work, but on the other hand if you like fiddling with your rig (I do) then it might be the right fit for your application.
If the skylight is two piece, would I be able to unscrew the interior piece and replace it with the tinted one? OR could I leave the original in place and purchase one of these to fit inside it and use velcro or something to fasten them together? My current skylight is the basic white opaque one. I really love having the light come in but not so much when it's 100 degrees outside We're getting all the windows tinted but they can't do anything to the skylight and I do not want to put one of those foil type things over it. So I'm just trying to figure something out while it's not so hot.
If the skylight is two piece, would I be able to unscrew the interior piece and replace it with the tinted one?
Probably not, the tinted one is probably the "hail shield" portion of it that goes on the exterior.
We're getting all the windows tinted but they can't do anything to the skylight and I do not want to put one of those foil type things over it. So I'm just trying to figure something out while it's not so hot.
After I read your original post and replied I realized that our shower skylight is actually tinted. The tint really isn't that impressive, it looks good and all but when you factor in that it's pointed directly "up" you realize that there really is a lot of exposure to the sun unlike a window that will only be exposed when the sun is on that side of the house. If you're looking for additional insulation you might want to consider using Mylar like you see in some RV windows, it's kind of like reflective bubble wrap. The down side is that it will completely block all light from coming in but it will also pretty much eliminate the heat problem you're experiencing. Then when the temperatures drop all you have to do is drop the inside skylight and remove it.
Personally, I'd stay away from replacing that clear hail shield simply because you'd have to remove the sealant that protects your roof around it. Re-applying is not too difficult but I just don't think that a tinted hail shield is really going to net you that much improvement. Here again, we all have our own tastes and requirements on these things.
We had the same problem with too much light coming in. Worried that when we went to Alaska it would stay to light in motorhome. We also have a glass shower door. Our fix was to get an extendable shower curtain rod, and a dark brown shower curtain to cover shower door. Worked like a charm and kept the water off the door, no more dripping onto floor when opening door, and glass door stayed clean and dry