What kit is it? One of the thinline Tele kits? The ply tops are normally pretty smooth and used closed-grain wood, so it won't take too much Tru-Oil before you start to build up layers on top of the base layers.you might want to stop on the top and get the sides and back up to a similar condition

To smooth the end grain, you'll need to go a lot rougher than 320 grit. I'd start with some 80 grit and then work your way up.