US Airways Dividend Miles (Pre-FlightFund Merger) - WHAT IS "2002 PREFERRED BONUS?"

I would be the last person to kick a gift horse in the mouth, but what is the "2002 Preferred Bonus?" My wife just had 250 miles post with this description. I checked the Bonus thread and didn't see it listed. Anybody know what this is?

It is merely one of the many magical ingredients that, when combined correctly, unexpectedly result in the experience that we call "tredecuple."