Didn’t they do things like the OT trooper voices by simply recording them over walkie-talkies? Even CB radios are still around in this crazy digital era we live in.
That makes sense, though I’ve never actually looked it up.
Though even if that’s how they did it for the PT and ST they’d still record it digitally and that might also make it sound different. Sound editing/effects is the part of filmmaking that I know the least about.