Is the Gemara on Daf16b (starting with Chananya ben Yehoshua above first wide line near bottom) poetic agada or how are the other words/text present on the luchos? Is this literal? Who explains it so?
It seems obvious from the context that the Gemara is to be taken literally, since the entire Sugya is describing how the Luchos were written. The Beis ha'Levi writes that the Gemara in question is confined to the first Luchos, but not to the second, from which, for reasons that he explains, Hash-m deliberately omitted any mention of the oral Torah.
This seems to support my answer.
Be'Virchas Kol Tuv.