Rolex 1680 Question

[andy66db]

I have a 1979 1680 with an early tritium service dial and matching hands that have turned a nice creamy shade, which needs a service (or at least a visit to a watchmaker — the whole crown and stem pulled out when I was setting the time) and I have two questions:
1. Will the London RSC service a watch that old and will they guarantee water resistance?
2. If they offer me a dial and hands replacement, which they almost certainly will considering the tritium lume has long ago faded, would a new luminova service dial and hands affect the value of the watch, considering the dial was a service dial in the first place?

I look forward to hearing [reading] your thoughts...