Some scholars believe that cave 7 contains some NT manuscripts, though 1 John is not among them. The fragments are in Greek, but only by rather creative and ingenious extrapolations can one make them a part of the NT. The best contender is 7Q5 (Qumran fragment 5 from Cave 7) which a Roman Catholic scholar, Jose O’Callaghan, and a German Protestant scholar, Carsten Peter Thiede, both regard as a portion of Mark 6. Most NT scholars have rejected such an identification, however. I would also reject it and have said so in print in both Bibliotheca Sacra and Westminster Theological Journal. It is very unlikely that the Qumran community would have any part of the NT in its belongings, since this group was as hostile to Christians as any Jewish sect (they were legalists to the core and separatists even from other Jews!). Further, the Qumran community was finally destroyed in c. AD 68. Although I believe that most of the NT was written by this date, that is debatable. As well, in order for portions of the NT to get into Qumran by this time they would have to have been copied so widely that non-believers were even copying them. That is highly unlikely within so short a time span.