'87 LeSabre power steering noise

1987 LeSabre with 150K, power steering growls constantly, louder when turning, etc. Reservoir full, still only a little harder to steer than normal, but annoying, been doing it for awhile.

1. Is this an clear-cut case of the steering rack needing replaced?

1. How much time, and how difficult, to performing the swap on these vehicles?
2. Is it likely the pump needs replaced -- instead of/ as well as -- the steering rack?
3. What am I looking at cost-wise for parts? TIA