I like your use of the wayback machine.... the first link I clicked off that archive page was talking about the USAirways code-share with United and look at this interesting promise they made:

Will Dividend Miles members be able to use their upgrades on US Airways code share flights operated by United, or on flights operated and sold as United flights?
Yes, upgrades will be available as a future enhancement to the program once the automation systems and processes are developed.

http://web.archive.org/web/200212041.../us_ua_faq.htm