I cut a one-piece floor from marine ply for a really old barrus dinghy.....I imagine it would have been no problem to cut it into sections, trim a bit off each, and fit some nylon hinges or just cord to allow it to be rolled up.
I wanted something really rigid, and moved it inflated, by van....hence the single sheet of ply.
Many years ago our Avon dinghy had the floor in 3 pieces of ply (8mm?) which were held together by 2 beams running the length on top of the ply with bolts screwed into bronze plates on the ply. Worked a treat though awkward to assemble which on the boat.
The floor on a Redstart is very thin. Fitting floorboards will form high-points that will wear through the first time you touch the beach. If you do make boards, ensure that edges are rounded and there is plenty of internal material intended to protect the floor. You may also find it useful to fit external sacrificial strips.