If it were me, I would want to at least try to get the paint off and see if I could get back to gelcoat. Paint over paint would give you a "ridge line," and then too, you are relying on the adhesion and quality of the PO's paint job to attach your paint.
One option you might consider is protecting the surrounding area while you try to remove the paint. Depending on how I'm going about it, I usually use blue tape and then some kind of plastic or paper sheeting. Kind of like an operating room, I try to make sure that only the critical area is exposed.
If you do use tape, you can make one primary layer, and then put another layer on top of it with the drape. That way you can change the secondary tape without messing up your good line on the base layer.
Know that you don't want to leave the blue tape on over a long time period (many days/weeks) because it will turn to "concrete" and be very hard to remove.
PS: Although, maybe it's just me - and I can't see it up close - but I kind of like the way the windows
look with the surrounds darker.