For the screw holes, you can get some small dowel, drill out the holes to match, then glue in pieces of dowel. If you can be precise about the depth, you can probably avoid any sanding and risking the finish. (Although you are also talking about stripping it.)
For the stripping, I recommend checking with our own Guitar Tech in his forum below. You will need a stripper suitable for the exact finish used on your guitar. I have also heard of finishes being sanded, and even "picked off" with a razor blade!
You can also search for some answers here. You can find pretty much anything you need to know: http://projectguitar.ibforums.com/
...so ever since then, I always hang on to the buckle.
