Found a copy of A Farewell To Arms, would like info

Hi there, I just found a copy of the book A Farewell to Arms by Hemingway, and I would like to know exactly how old it is for my own personal knowledge. The only copyright date listed is 1929, the date the novel was first published, although I know it is at least 20 years newer than that because there is an introduction by Robert Penn Warren which contains citations to works published as recently as 1948. Other than that, there is nothing pointing to an exact year of publication, and I'd like to get a better idea of how old it actually is.

Does anyone know anything off the top of their heads, or know where I can look to find out? I searched the web a bit but found nothing helpful.

Thanks

Is there any chance this could be it? http://www.amazon.com/Farewell-intro.../dp/B00170DD5G