That is understandable. If you're curious, it's pronounced the same as "ought" (or Ott, I suppose). The word "ought" is frequently used where "aught" should be used instead.
These days you hear it more frequently only in certain areas, such as describing cable (00 or "double-aught" cable), bullets (.30-06 cartridge or "thirty-aught-six"), or, as used in the article, for years. So, if you're, say, a gaffer, a mechanic, or a gun collector (or an old-timey prospector), you have more of a chance of having used the word "aught."
However, if you're a Tom Waits fan, you've been using "ought" in its place. "16 Shells from a Thirty-Ought-Six"
While, I am Tom Waits fan, I am not an English language expert, so anyone in the know, please correct me if I've written any misinformation here.