Line-X and 3M 4200

Anyone know if Line-X is compatible with 3M 4200 marine sealant?

I'm going to Line-X my fiberglass swim platform on my '79 Mastercraft and want to seal it with 4200, but the local Line-X rep isn't sure if it will stick or not. The platform is going to be a combo of thru-bolted and/or lag screwed with 9 screws/bolts, so that in itself should be good, but I 250+, so I'm after something with some adhesiveness too.

Any thoughts on going with the UV Sealer vs w/o?

I kind of like more of a matte look as my boat has a matte rub rail and trim, but wasn't sure if it grey out over time. A few of the Line-X threads on here indicate that it still looks fine after a couple years, but they're older threads so I figured I'd ask again.

Thanks!

Sorry, should have wrote, want to seal the holes and the surface between the platform and the transom as it was done from the factory.

yes
just make sure the 4200 is cured