Replacement Wooden Deck Color?

The color is ... it depends ...

It depends on the ship, nationality, and time period.      You will need to go out and research your subject and evaluate what you want to portray in light of these criteria.   Your laser-cut deck is probably linden (basswood).   Not all ship's decks were oak,  some were teak, others cypress,   some were even pine.

Whatever you decide, you will want to go with a good hardware-store brand of solvent-based (not waterbased)  stain and/or sealer.      You want to apply the sealer to both sides and all edges of the wooden deck.   A water-based sealer WILL cause the thin wood to warp.   Failing to seal all open sides and edges may eventually lead to warpage from the humidity in the air. 

I think I would go with a brushable stain/sealer, thinned well and perhaps applied with an airbrush for thin even coverage. 

During the actual war period most ship decks were painted in the appropriate camoulflage scheme. If you are depicting prewar, with natural decks, both teak and oak weather rapidly to a grey- teak a light grey  and oak a somewhat darker shade.