Well, it doesn't sound like you'll have any problems. Why the valves were surfaced, I can't say. Perhaps they previous owner had too much camshaft and thought shaving the valves was good enough to get by. If he took enough off to make the edges of the valves near "sharp", then I would suggest getting new valves for it.
The copper sandwich type is the original style which requires re-torquing. I wasn't aware they still sold those. The best ones to use are the Felpro or Victor ones with the steel borders. The Victor ones have a couple of the front water holes blocked off to force more water to the back of the engine. I have used both of these gaskets without any noticeable difference in cooling (on the same engine), but I would still opt for the Victor one.
