First off, I'd just replace the pads and cables. A little bit of rust on the brake nut or a little corrosion on the arms is no big deal- safety is the most important thing and the original brakes will stop just fine. Lube the pivot with a tiny dab of tri-flo and you're good to go. Borrow a buffing wheel and some Zam if you want the metal parts to shine, but classic parts on a classic bike are just better looking, IMO.