Here are two paragraphs from Stephen Hart, writing in MLR 97:3 (2002): 602-19:
“In an essay which was surely intended to publicly humiliate Georgette, ‘Los poemas póstumos, a la luz de su edición facsimilar’ (1974), Larrea sought to attack the very basis of Georgette’s authority. It is a devastating attack and reduces to rubble two very important butresses of Georgette’s argument, the first of which concerns the titles of the poetry, and the second of which concerns the issue of the chronology of the poems. The bulk of Larrea’s argument is based on the typewriters that Vallejo used in typing up his posthumous poems and it is so detailed and conscientious that Georgette — not trained as an academic — would have felt very wary of responding. Larrea used a very sophisticated, convincing argument about which typewriters had been used when in order to make some humilliating claims; firstly that Georgette put ‘¡Dulzura por dulzura corazona!…’ at the end of Poemas humanos in order to give the impression that Vallejo’s last thoughts were for her (pp. 67-69). He furthermore attacks the idea that Poemas en prosa and Poemas humanos are two distinct volumes of poetry (pp. 80-85). Most importantly for our purposes he also argues that the date of typing is also the date of composition (p. 74-75). At this point one could speculate that Georgette, who had the pre-typescript manuscripts in her possession, would only have needed to look at them in order to discover that, in fact, Larrea was right and that the date of composition was the same as the date of typing up, as a comparison of the dates on the manuscript and the typescript shows. This caused her, again we may speculate, not only to conceal the existence of the manuscripts — though she had slipped up by letting one rogue copy end up in Ángel Rama’s safe — but, also, to destroy them before her death. This is one reason why, I believe, we at our peril ignore the venomous debates which have surrounded Vallejo’s work.”
“This new chronology of Vallejo’s Poemas humanos seeks to differentiate between Georgette’s and Larrea’s version, and avoids positing a major fault-line, as it were, in Vallejo’s work around which all else must be positioned. Georgette sought to base her understanding of her deceased husband’s work around a dividing-line which separated the non-political from the political works, and thus she divided Poemas en prosa from Poemas humanos, and promoted the view that 1931/32 was a period in which a major paradigm-shift took place. Larrea, for his part, believed he saw a clear dividing-line in Vallejo’s work between those poems which focused on Spain and those which did not. In a sense both Georgette and Larrea were right about certain aspects of Vallejo’s life and work, but the problem grew when they attempted to impose their authority to give judgement on areas about which they had imperfect knowledge. The aim of this essay has been to use an independent piece of evidence — the pre-typescript manuscripts unearthed by Juan Fló — in order to create a new chronology of Vallejo’s Poemas humanos, one which takes the most reliable parts of each version to produce a new way of looking at an old problem.”
The manuscripts Fló found among Rama’s papers are indeed key, and they are probably the ones I should work on. We can read the full text of Hart’s article at the Instituto de Estudios Vallejianos.