I am about to install the new floor in my 1965 Alumacraft Bel Mara. The best that I can tell (since the front half of the floor was replaced once but the back half was still the original floor) is there was never any floatation foam under the floor from the factory. Do you guys think I should install some before I put the floor in, or since the factory didn't think it was needed - leave it out? Thanks