They leave scars, sure...I don't think Nepleslia has progressed to the point where cutting someone open doesn't leave a gaping hole. However, those scars can be healed to the point where they aren't noticeable. I figure we've progressed that far, since we mess with genetics on a daily basis nowadays.
And...really, we haven't laid out all of our systems planet-wise yet, so your guess is as good as mine as to how many Saturn-size gas giants we have. If you have a suggestion for systems and planets, though, I'd be glad to hear them and consider adding them to the systems' wiki page.