Well, you appear to have taken my 'where it can be established...' to mean something other than what I meant, if you mean can it be proved beyond doubt then of course no, that would be literally impossible, but there are certainly things that can safely be taken to be allegorical, or non-literal at least, on the basis of the evidence in the text itself.
On a bit of a tangent, but relevant I think, is the authorship of the Torah. It is an article of faith for some, for reasons I don't personally understand - perhaps because this came out of the Jewish tradition? - that Moses wrote the Torah. However there is clear evidence of different styles, indicating multiple authors. In the same way as you can read say Mark Twain and Bulgakov and identify differences in style, scholars of Hebrew can see the styles of different authors in the writing of the Torah (as we have it).
Another issue is the use of numbers - 40 for example, used to indicate 'a long time'. The Israelites were in the desert for 40 years - were they? In ancient writings numbers were used freely (in the Sumerian king list kings ruled for 10s of thousands of years) or symbolically, often. Clearly the writers of the OT didnt have the same relationship either with numbers, or dates, or accurate reporting for the sake of accurate reporting as we do, in the modern world. They thought about the whole business very differently, as is evident in the text.
Anyway I realise this kind of thing requires a paradigm shift in thinking, and I don't have the time to put into going through the layers of it, but there is plenty out there you can read about this kind of approach to study of the bible, you might find it interesting.