It would have been taken up again, expanded, developed, metamorphosed.

That is possible, and, for my part, I am of those who, like Brunet and Nodier, are inclined to think that the Chronique, in spite of its inferiority, is really a first attempt, condemned as soon as the idea was conceived in another form.

As its earlier date is incontestable, we must conclude that if the Chronique is not by him, his Gargantua and its continuation would not have existed without it.

This would be a great obligation to stand under to some unknown author, and in that case it is astonishing that his enemies did not reproach him during his lifetime with being merely an imitator and a plagiarist.

So there are reasons for and against his authorship of it, and it would be dangerous to make too bold an assertion.
One fact which is absolutely certain and beyond all controversy, is that Rabelais owed much to one of his contemporaries, an Italian, to the Histoire Macaronique of Merlin Coccaie.