I don't think I ever had the SS plates off this area before. However my trunk fiberglass around that area is solid.
You'll probably get a better idea what to do as you dig into how bad the delamination is and what was used for a pin bushing before. I've also heard there are shims on either side of the centerboard on the pin to hold the centerboard snugg in the trunk tunnel. I don't think mine has them anylonger. PO took the centerboard out for sanding and epoxy coating in the late 90's.
Let us know your progress. Good luck!!
Rehoboth Bay/Indian River, DE
S/Y KJ, Helms 25