my WB 120 at that time had softwood (maybe Spruce) as end pieces on aluminum spars and mast, marine plywood behind GRP as bulwark and waterproof glued plywood on rudders and centerboards.
I built the bulwark, gaff and boom from oak during the refit, the mast from Canadian Spruce and the centerboards from marine grade aluminum.
I sanded the wooden rudder blade and sealed it with several cages of epoxy resin. I covered the benches in the cockpit with oak.
Hope this helps.