"(For not the hearers of the law are just before God, but the doers of the law shall be justified. For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves: Which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another; )" - Rom 2:13-15 KJV
This depends on how "Gentile" is being defined here. If we see Adam, Job, and Abram as Gentiles, and everyone else before the Abrahamic covenant, it is clearly the case that law has always been written in hearts. And by that an unmanifested form of scripture has been there since the first moment. But part of that law is to faith. You can take the position that neither "faith alone" nor "scripture alone" preceded the other.
Not to be a heretic in the "First Church of the Optional Poll" here, but I think that if the question is about Luther's "faith alone" and "scripture alone" that your poll is taking it out of context. They are apples and oranges.
Between scripture and built up doctrine, we should be able to find the answer in scripture alone. Between faith and works, salvation comes through faith alone. There is no competion between "faith alone" and "scripture alone."
You can agrue against sola scriptura and faith alone, but at least recognize that they are not competing concepts.
If you were to ask instead whether faith existed first, or whether the current Biblical canon in a written form existed first, it is compellingy the case that faith came first.