Well, if the finish is not glossy now (like really shiney) it should have been oil finished from the factory, but could be some other type of material. As long as it porous, you can just work with that finish. If it is totally hard and glassy, then you may need to strip it down a bit with some 300 to 400 grit sandpaper to take the gloss off. There are three products from Birchwood Casey. 1) the Tru Oil, 2) the Stock prep/conditioner & 3) and a really nice Wax. After giving the stock a real good cleaning, using some bore cleaner or lighter fluid if needed. First, give it a good going over with the stock prep/conditioner. A couple to 10 times may be required. See how it looks, if the stock buffed out nice with the conditioner, then apply the wax. Light coats, letting it dry up in between, maybe 10 to 20 coats. If the conditioner didn't buff the stock up nicely, then sand the stock lightly as mentioned above and begin applying the tru oil with your fingers (sounds weird but even they recommend that). Lightly sand in between coats, letting each coat dry thoroughly. You could be looking a 15 to 30 coats, depending on how nice you want to make it. Once you are finished with the oil process, then use a couple coats of the conditioner, then wax it up. I did a Walnut wood guitar once, with about 100 coats of Oil, and 20 to 30 waxings. each coat of Oil took about half a day to dry thoroughly to my satisfaction, so you can figure our how long it was in the finish stage.