My understanding is that the negative would have been on A/B rolls, with the subtitles on a C roll. So they have to run it once without the C roll to yield that IP. So whether it's done before or after the one with it, either way isn't it a totally separate event, possibly done by different people, different day, different equipment even? I remember James Cameron saying that part of the process was so wildly hit and miss he would make the labs sign a contract that the first answer print he was seeing really was first, because labs would fuck it up the first time and do it again without telling the client the negative had been handled more than he was told.