The issue with the majority of the fittings along the hull/deck joint is the cabin/hull liner getting in the way, although at least the nuts are visible inside the anchor locker on my boat. I found that a Dremel tool (pick your fitting, the small sanding drum seems to be popular) is a good way to grind away the glass liner to get better access to things like the outboard genoa track nuts, or nuts securing cleats, etc..
On my old boat, hull #511, I've noticed the aft cleats (tiny little 6" cleats too) have a minimal alum. looking piece of angle as a backing plate..Doesn't seem sufficient to me (& mine are loose) so I'll be making a larger backing plate when I replace the cleats with larger ones. I didn't notice a backing plate of any kind on the forward cleats.