Restored SS Class A amps

The Aleph series by N Pass still holds its own today. If I still owned some I'd send them back to Pass for a check-up.

Further back in time to your point, I would reckon a rebuilt and tastefully modded/refreshed Bedini 25/25 would be stonking.
Early Classe' amps by Reich make me wonder.
Mods are either aberrant or replace/improve original components, e.g., caps, with modern or "better" - or just more expensive- bits in the circuit. I'm having some secret old school amps and turntables refreshed/updated right now. No idler wheel TT, hobbiest stuff, off topic.

Many audiophiles drool over mods of NEW components , just like cars, that make them feel good about having spent the money. I'm not speaking about bonzo75.