Spray's semi-planing hull underwater is claimed to be identical to the hull American Marine used for the GB36 (and all the subsequent models until the most recent "fast" GBs).
Above the waterline there are some stylistic difference, mainly the break in the sheer a little more than halfway back. But the underwater lines, angles, etc. are identical according to everything I've read about American Marine, Spray, and the GB36. Spray was even given an "honorary" Grand Banks hull number, GB36-000.