Years ago I heard Brian’s old band Geordie I think? A bud was huge into AC/DC and found the cassette somehow. It was far different than his ‘falsetto on steroids’ thing he does.
But, I will say this: it was far easier for me to cover Bon era songs, than Brian vocally. Not any of my old singers, nor myself when we were a 3 pc could pull off Brian era stuff. One guy in our area could. But that was it.