Based on a true story: Hemingway reference in movie
The kernel within this whole story's premise---losing one's life's work--is true. Hadley, Hemingway's wife, was in possession of a batch of his short stories, all written when he was a young ex-pat in Paris before he became famous. She did lose the case with the manuscripts in it. And they were probably thrown in the garbage, never to surface again.
But Hemingway was undaunted as would be any writer of any talent and mettle. A writer has the story ideas in mind still and can reconstruct from notes and journals. It would be tedious and the re-construct work would not be word for word, but might even be better as it has been "rehearsed" and now in the re-telling might be burnished, added to, honed.
True, the heat of the moment in which the stories were written is gone. But heat of the moment is much overplayed in our conception of how writers write. Even Kerouac edited for years at a time what he had initially free-written.
The movie was corny big-time,but I rather enjoyed it.