I guess they didn’t bed/seal the portlights with 5200 back then. That stuff seals great but it is difficult to remove.
I have 6 to replace. The first 3 came out great....nothing but silicone. The fourth one almost killed me, they slathered it in 5200. I had to do some gelcoat repair after I got it out. Luckily the repair is under the MR10 and sealant so I didn’t have to do all the sanding etc.
Am starting the last 2 this Friday....pray for me. I am hoping that they are just silicone.
Oh yeah and the portlights that were just put in with silicone were not leaking at all. The one with 5200 had a very small leak that I never could find. The inner board was a little damp when I finally got it out. Not enough to cause any rot etc so it must not have been leaking long.