The BBC reported on some first century books, that were discovered in Jordan, they have early Christian symbols. The obvious question is: Do they pose a problem for the Church?
The answer is: No.
Christ promised to be with the Church until the end of time to guide her into all Truth, etc. etc.
First of all we have to judge whether they are "Christian", that is are they part of the Apostolic Tradition, as opposed to a Chritian sub-group of which there seem have been many, especially between the resurrection and the destruction of the Temple.
Do they alter Revelation? No, because the Tradition didn't count their contentents, whatever they maybe, as reflecting what had been passed on to the Church. We judge what they might say against what the first witnesses the Apostles taught, in the scriptures we have.
What they do indicate is that "Christian" writings are actually early, the letters of the Apostles all predate the destruction of the Temple.