Go with the record, and the footage of his opponents! This man was top three all time pound for pound easily!
But he COULD actually fight like that, we can't objectively know, because this is all we've got. Obviously I don't think actually fights like that, but the point still stands.
And if he did fight like that, and compiled the record that he did, against the competition that he fought, it would be a stupid mo fo that would write him off as failing the "eye test". A smart mo fo would be the guy that sees someone fight like that and be incredibly successful and think that maybe I don't know what I think I know. And you put appearances aside and start studying what makes him effective.
If I'm completely honest, if I had people who saw him fight tell me that he fought like that, I'd say "Wow it's crazy how far boxing has come, yesterday's champions are no better than todays journeymen." That's my honest opinion.
