Those are combing pads - they will be vinyl covered - they aren't actually stained, that is a pourous wood sealant - to stop them from warping over time from moisture absorption. After talking with some plywood pros, I learned that "marine grade plywood" was really nothing more than AC exterior grade that is voidless. I did a lot of searching about the best wood to replace the old, mostly rotten wood that was in the boat, and this is what I ended up with. I used 1/2" 5-ply instead of the 3/8" 3-ply that was in the original interior. It probably added 10 lb to the gross weight of the boat, but the 5-ply holds up waaaay better. THen I sealed it with the sealant you see in the last pictures. I think they color it so that you can see what you've covered already.
Vinyl should be here next week - I'm going to replace most of the foam, as it has mildew and is pretty ratty. 25+ years will do that to foam.