I don't think the rudder is going up in the slot. I agree with Lunacy. The ruder and skeg has to go up together with the pintle. The skeg is sitting on the pintle as it goes up, with sealant on it. Then aligned up and bolted tight. Then fairing compound is used to fair the joint.
The upper fiberglass faring is not attached to the skeg and should be very thin on the edges. It looks like a channel that is bolted to aft vertical flat section and only has a little fairing compound on that joint, it should not be glassed to the skeg on hull. You can see the old bolt holes in your photos. On my T37, that is the original design, the fairing is wider, or opened up more. Check out the below link.
https://photos.app.goo.gl/11x3nfcjbGM168nz9