It depends on your vision for the bike. Keep it stock, cafe, rat it out, chopper. If the exhaust is stock and pretty solid, any small holes could be repaired with some welded patches, and the whole set rechromed. If they are in bad shape, the alternative is replacing them with aftermarket or new-old-stock parts.
As far as rechroming, the best bet is to find shops in your area, show them your exhaust, and see if it's in your price range. Make sure you and they understand the scope of work, so there are no surprises from start to finish.
Good luck, and keep in touch. We're here to help if we can.
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.