Ah yes, forensic bibliography strikes again.

That was my field when I was an academic. I did the history of printing (did you know that Shakespeare spelled it in manuscript "Cresseid" rather than "Cressida," but the "SS" ligatures available to the compositor were all used up, while the "SSI" ones were not?) for my doctoral studies. I don't know much about modern bib, just that generally the quest is perceived among the hoi polloi to be that of finding "what the author intended." But academics quibble on that; and sometimes decide that it's more interesting to find "a variety of potential interpretations" which provide a "variegated poet-scape" or some other blather.
Frost's handwriting is pretty thick. Could he read it himself I wonder ...