THX for the phots Rip....
mine has a floor that runs all the way to the nose...stringers can't be seen unless you open the door to the ski locker, but I can see how that would stiffen the deck considerably.
I can't see where there was any past repairs or holes where they may have been attached at some point like on yours, so im thinking it did not come with them.... there is no stress cracks or crazing on any of the deck surfaces, so it may just be " what it is". In the meantime, i'll stay to the sides if I need to go on the deck.
THX again for the photos