Can you remove rudder and drain hardware off the hulls?

I just bought a 16 that needs a bit of work. I need to remove the hardware off both hulls to repair and paint the boat. There must be some sort of threaded backplate for all these screws. Are they bedded in the 'glass? Or will they fall and rattle around forever lost in the hull:)?

There's an aluminum plate that's glassed in to the back of the boat.

You can take the gudgeon bolts out, no problem.

Be careful putting them back in - don't push too hard. You can dislodge the plate.

I did this when trying to drill out a bolt that had sheared off. I ended up having to cut a port into the deck to access the inside of the transom.