Keep in mind, unless you go through any old amp, blueprint every component for drift, possibly replaced the electrolytic caps, possible replace the tubes, and (in SF Fenders) possible replace the speaker, you haven't any clue what that amp can sound like. The reason there seems to be a lack of consensus on many amp models is because any too vintage amps can have drift up to 25% or more from each other in the way the circuit works.
If the amps 25+ years old, until you account for every single resistor, cap, etc. in there, it's a crap shot. That's why I don't recommend old "bargain" amps anymore, if someone doesn't know how to go through the amp and do some maintenance, then they are on the hook for bench fees for any necessary TLC.
Valid points, all. Thanks for the input Wyatt.