If there's no grout, then there's very little chance of damaging the surrounding tiles by pulling them out. However, I'd try and sand them first. The trick is trying to figure out what grit they were finished with originally, so that they'll match the rest of what's on the floor. This can be done by trial and error. Start by sanding the scratches out with about a 200 or 22 grit. Once the scratches are gone, I'd start with a 400 wet and dry. If that's not enough, step it up to a 600 wet and dry. Next, to an 800, if it still doesn't match. If after that it still looks different enough to the point where the pieces would stand out, then I'd say the heck with it and change them out. But try the sandpaper, first.

Follow up- this worked great. Thanks for the advice Bill.