If a writing is inspired, then we must ask the question of who it’s inspired by. Obviously, I believe “inspired writings” are writings inspired by God. God gave the inspiration – this happened at or directly before the time of writing. Whether or not man recognizes God’s inspiration is another matter.
Clearly the scriptures themselves were recognized as scriptural before the canonization of the New Testament. The letters of Paul traveled in collected form by the end of the first century, being read in many churches. A list of scriptural books exists from the early second century (I believe), containing over 20 of the 27 New Testament volumes (omitting only Hebrews, James, II John, III John, and Jude…maybe II Peter).
Ask yourself this – If the writings of Paul are considered inspired today (whether that determination is made by the RCC or you, or some other entity), why would they not be considered inspired at any time in their past? Did the content change? Do you believe God’s truth has changed at all? Surely not. Thus, the same content was inspired by the same God to reveal the same truth. Time, and the recognition of man, is irrelevant to the factual status of this.