The Parayana is a ghostly text in northern sources compared to the Atthakavagga, but the two do get mentioned in the same breath by a couple Sarvastivada sources. So, a text or collection with the same title existed in at least one other Buddhist canon. That’s not the case with the Atthakavagga, however. A good case can be made that it existed in multiple traditions and is indeed very old.
I took the time to summarize a bunch of references to these two texts in Chinese Buddhist sources (i.e., Indic texts translated to Chinese) in another thread. One of that things that’s hard for me to ignore are the Vinaya stories depicting disciples reciting the Atthakavagga parallels during the Buddha’s time. At the very least, it means it was old enough that Buddhists in the 4th c. considered it as old as the Buddha.