It can be scratched. Corning Gorilla glass 3 is a champ, but the small form factor and the round shape contributes to a little less consistency with the scratchability from person to person. I developed 3 rather annoying scratches within the first 3 days of using it. They weren't deep, but they would show up in certain lights and it made me hate the watch. Luckily a nice screen protector made them all go away. So if your scratches aren't too deep, don't bother getting it buffed out, or God forbid buffing it out yourself. One you wear away the oleophobic coating and two, ain't nobody got time for that! Screen protectors will fill in light to medium scratches. I used 2 on my Moto 360. First the ArmorSuit MilitaryShield, mostly because it was on amazon for cheap. It worked great, but had a little too much of that grippy texture to it. I'm a huge fan of Phantom Skinz and they have a great whole body protective skin. Their matte finish also reduces glare which is a plus. I don't get paid to say any of that. I just like them. I've had Phantom Skinz since back when I rocked a Palm Pre a loooooong time ago.
EDIT - Note: This does not remove the scratches, it merely covers them up. When you peel away the protective cover, the scratches are still there.