"Standard Apple Keyboard" is insufficiently specific for this discussion, I'm afraid. The
Apple Keyboard with Numeric Keypad—the default keyboard which ships with current Mac Pros—does have an fn key. This aluminum keyboard was originally introduced in late 2007 (that's when I got mine), and AFAIK, it's been the "Standard Apple Keyboard" for going on three years now. (Though iMacs ship with the wireless version standard and the extended keyboard as a build-to-order option—just the reverse of the Mac Pro.)
On this keyboard, BTW, Exposé's
All Windows feature is, by default, invoked via F3; invoking it via F9 requires holding down the fn key. More info on this keyboard can be found in
SchwarzTech » Review: Apple Aluminum Keyboard.
