They were never, nor would they ever be metal. Back in Black is the closest and that sounds like a cranked 800...not even boosted. AC DC are the kings of '3 chords and a cloud of dust' hard rock. No matter what era/singer. Angus is a bluesy player..that's what some shredders I've heard over the years forget to do....play with great vibrato, play with feeling/develop a 'feel' for the instrument. Angus is a world class lesson on how to do it. Learn to play like Angus first, then learn shred.....
One of my fav bands ever...think about Angus doing his 'hop' thing for THE WHOLE FREAKING SHOW and you then realize how great he is. He's (and the band) a treasure.