I would say that ultimately accepting the credibility of the divine claims of any book must have to be based on the nature of the writings of that book. More than this, if the Spirit speaks from the words of the book and is understood by the indwelling Spirit in our hearts, that is when the claims of divinely inspired writings become credible.
WE also have to acknowledge though that much of what we hold to be true has been given to us and has not come about as a result of a completely independent analysis on our behalf. This holds as true for the church as for the bible. It would hold true for the Koran too if we were born or absorbed into that culture.
Ours is also a culture that has learned how to critically examine truth claims. This is to our great advantage.
So on the one hand we would have a group of sincere, educated, and dedicated gentlemen seeking out the religious texts that were the most widespread and deemed to be the authentic ideas of the apostles. On the other hand, we have the incredible claims that an angel appeared to a man in a cave, and the words of the angel were eventually written down verbatim, not a jot or iota out of place, on clam shells or other like materials, and then the original copy destroyed by Abu Akbar and his own version of the rapidly expandings transmissions of Mohammed arbitrarily made the authentic one. (And coincidentally, some of the stories are not unlike those available in the Christian apocrypha at the time as well).
To determine credibility then one must consider the superlative nature and content writings themselves, and consider the process through which those writings were authenticated as being from either an apostolic or angelic source, according to the varying claims about them.
The question arises then, do the people who authenticate the claims of Scripture thereby deserve special consideration and a special chrism as a result of a job well done?
Some claim that to be so. Likewise, some claim that scientists in white lab jackets also have the special charisma of truth now too as they have become the new priests of the modern era.
Nevertheless using credible methods for determining Scripture as authentic really does not distinguish the churchmen or the scientists themselves. It is their methods that are credible, and as such their methods are replicable by others too. There is no special powers involved, no special chrism at play here either. Good methods authenticate the texts just like they authenticate the discoveries of modern scientists. It is poor reasoning that if one believes in the result one must also believe in the divine authority of the people who gave us those results. The results are a product of the method and some divine authority handed down to the people who decided on which scripture in the first place need not be involved at all.