I don't
recall the
Cal folks doing cored hulls in general. However, you should be able to determine the construction by simply inspecting the area where the
hull meets the
deck. Cored hulls will have a transition area where the coring ends and the hull tapers down in thickness for the flange. It is pretty obvious in most cases!
Nonetheless, doing the "waterbag" test is a good idea, for it will help you find the best spot for the mounting.
Jim