Dave Artie ,Here is how that mold system worked the stringers were done then the Bulkheads were placed inside laying down, the deck mold with the finished part was then placed on the hull mold (the cutting flanges were "Keyed") then 360 glass, the bulkheads were then stood in place and glassed in then the deck mold was removed as shown here.

That new Sport deck would just be done in the same manner with the molds flange to flange glassed then demolded.