This is to share my experience in removing and re-installing the skylights (tinted, curved, lexan panels) in my 1990 SCR-2700.
The 'plastic' on my boat was in pretty good shape. I'm told that they were replaced about 6 years ago, but they still leaked when we had heavy rain. Because mine were replaced at least once before, I can't be sure how close this is to the orginal factory installation, so some things may be different on your boat.
To remove them, first remove the eight screws. Then start digging out the black caulking between the skylight and the fiberglass. Take your time and try not to scratch the gell-coat underneath.
After you have most of the old caulking out, try to lift one corner of the skylight. I would be careful not to try to flex it too much as you wouldn't want to crack it. If you can slowly lift one corner, and then insert a small heavy line, something like a stainless steel fishing leader would be perfect.
With two people, use this line to slice through the remaining caulking and gasket that is holding the skylight firmly to the fiberglass, with one person inside, and one outside, using a sawing motion with the line. This allows the skylight to be removed fairly easily.
Once removed, continue to clean off all of the old caulking and any adhesive off of the skylight and also the fiberglass. This is a tedious job and it took me a couple of hours to clean it off. I used some scrapers, being careful not to scratch the skylight nor the gell-coat.
After all the caulking residue is removed, clean the area with a solvent (3M general purpose adhesive remover, or SEM SOLVE), or even with some acetone. You want to clean both the channel in the fiberglass decking and the area around the skylight.
To replace the skylight, I used some 1/2 inch 3M Super Strength Moulding Tape (Purchased at a local VIP Auto supply), and place this around the perimiter of the skylight first. Then I placed a couple of ice-picks through the mounting holes from inside the cabin to help me align the skylight as I placed it down on top of the fiberglass deck (the 3M moulding tape is very strong and once you touch the skylight to the fiberglass, you may not be able to move it around).
After the skylight was in place, I replaced the eight mounting screws and tightened them down. I did this in an alternating pattern similar to how you would tighten the bolts on a cylinder head or when replacing a tire.
I then used blue masking tape to mask off the deck and skylight. Make straight lines and nice corners.
I then used black 3M 4000UV to caulk around the skylight. First I used a small bead directly to the joint between the skylight and the fiberglass deck. This was to ensure that any and all gaps were filled.
Then I proceeded to fill the joint up with the black 4000UV. When I did the first skylight, I made the mistake of doing this when it was hot and sunny, then I proceded to fill around the entire skylight before smoothing out the caulking. By this time the 4000UV had started to set, so the smoothing of the caulking was not very pretty. When I did the second skylight, it was a bit cooler and not in full sun. I also smoothed out each side, before I started filling the next side. This worked well!
Before the caulking starts to setup, remove the blue masking tape. Have a razor blade handy to trim any sticky spots that start stretching the 4000UV away from your joint if the caulking has setup too hard on top of your masking tape.
Afterwards, I removed each mounting screw, one at a time, and added clear RTV under the screws to help water proof them. I didn't want to use the black 4000UV in fear of getting any of it inside in the cabin on the headliner.
So far these skylights are waterproof again.
I'm sorry I didn't take any pictures during this.