I seriously doubt they threw away any of the original negative, even the sections deemed unusable. You never throw away your originals. Lucas is notorious for saving everything anyway. But if there was any sections of the original comps that were not presentable because of deterioration it would be no big deal, you just get them from other sources--Ips, separation masters, etc. Some of the shots in the 1997 SE (and on into the 2004/11) were taken from those sources because the negative was no longer any good. They cut in pretty seamlessly.