only thing you can do is remove it and put it on the water and check for twisting ao flexing. you can always get new rivets and put the bench back in, or does your bench connect to the floor along the whole bottom of the bench? if so just cut out the middle part of it and you can use the peices on each side that will still be riveted and make 2 small storage boxes. or remove the whole thing and make a brace for each side, do a search and you will get a few ideas from others mods. honestly though i dont think you will have any problems with rigidity with that small of a boat because im guessing your motors small and your not out jumping whitecaps and wakes.....i removed my middle bench on my 16ft v and its fine.