Evangelicals typically think that the Canon is now closed, static, fixed, and our final authority on ALL matters in Christian life. This usually is justified (amongst other reasons) by the notion that it was the apostles who alone had some kind of superior access to revelation from on high that no other human being since has had. Hence, when an evangelical is confronted with the arguments that some of the books in the NT were forged by people claiming to be apostles who actually weren't, their notion of the inspiration of the apostles is challenged which in turn challenges the very inspiration of whatever book may have been forged. I think a promising route to go would be to adjust ones theory of inspiration so that the Christ-event within its religio-historical context becomes the control for our theory of inspiration (as well as the basis for the FACT of inspiration) in such a manner so that apostles, and non-apostles are capable of not only producing, but judging what it is that is 'inspired' in the NT. The upshot of this is that forgeries in the NT can still be inspired since it allows for books in the NT written by non-apostles to be 'inspired' while at the same time giving us some objective criteria to judge these forged books by to determine the nature and extent of their inspiration. So, to put it in catchy terms, the NT (and the OT) is inspired from the 'bottom up' but finds it center and factual basis in the only 'top-down' revelation known to mankind, namely, the Christ-event. So, I think a plausible message to take from the nature of the Bible, and forgeries in particular, is that non-apostles are just as capable of discovering 'bottom-up' God-inspired truth as the apostles were so long as the Christ-event is our control. What this means then, is that the evangelical understanding of the canon is incorrect in an important sense. To see what significance or authority the canon can have on such an adjusted view, see the post below this one by James D.G. Dunn.