Question about "Date Added"

I have a question about sorting by "Date Added." Noodlesoft says in their FAQ:

Date Added" is not an attribute recorded by OS X so Hazel records it itself.

http://www.noodlesoft.com/faq.php#U5

However, if that is the case, how come a basic install of Leopard knows about Date Added, and lets you choose that sort mechanism in a the dock/stacks?

See screenshot:

Right now I am using Hazel and it's labeling downloads with colors to help me differentiate between new/not so new/old. I am also running a Folder Action to "touch" files as they are added to the folder (so modification date is updated.) Lastly, I created a Smart Folder to show me "Today's Downloads."

But it'd be a lot easier if Hazel and Leopard could cooperate on the built-in "Date Added" thing. And why doesn't Apple have "Date Added" as an available choice in Leopard's standard "View Options?" Just all seems so odd to me.

I realize now that Hazel was written pre-Leopard, so this "Date Added" attribute might not have been available at the time of it's development. (And the FAQ might be outdated as a result.)

If that's the case, and the "Date Added" metadata is available to users and developers, then consider this a request that future versions of Hazel take advantage of it.

As far as I can tell, the "Date Added" in Leopard is not available. It seems like it's totally private to stacks as you can't use it in smart folder queries nor does it appear in the "Get Info" panel.

It's something I'm still researching but as far as I can tell right now, it's not available outside of stacks so Hazel can't do much to take advantage of it.