Hi Jim!
At the stern on the starboard side there is a stamp in the hull telling you wether it's a factory finish or a kit boat, and the hull number, and date of build. If it starts with wssf it's factory finish, if it's wssk it's a kit boat, then the hull number, and then date (month and year) of build.
We have teak decks on our boat. A couple years ago we removed the decks to re-bed and re-caulk. The caulking was pulling out in a bunch of places, and we were worried about water getting to the deck underneath. As it turns out, the bedding was very good, and we could have saved ourselves a lot of grief by just ripping out the old caulking, giving the wood a good chance to dry (being in Canada this can be difficult), then re-caulking. We also had a bunch of screws pokeing through the deck (it had worn over the years and the plugs were paper thin). If you can avoid removing the deck, the job is MUCH easier. You mentioned the seams bulging above the wood... IF the seams are well stuck to the wood, I'd leave it 'till you need to do it (it adds grip, and teak is often difficult to bond to).
We also had to replace the sampson posts (they were wood with no finish at all on them when we bought the boat). The old owner had siliconed the under side in the chain locker, and water pooled down the side of the sampson post, rotting it and a bit of the deck around it. Fortunately we caught it early enough, and it hadn't spread too far in the deck.
Look for mast compression, lots of these boats have had problems with that. Bud's Westsail Service Manual is well worth the cost if you get into this project. Westsails are great strong boats... I wish you the best with this project, and welcome aboard!
Meaghan