OP
20-year-old amps, as other have posted is just at its prime (as long as it is not abused). If it's a Pass, then it can be recapped if you wish at the factory.
I would grab that offer (if it's a Pass) right away assuming the price is right
My old amps were Rotel and one of the first Decware amps. these were about 20 years to this day, and they all sounded great, no need for CAP changes.