I think it depends on whose definition you look at but Glam definitely has a fashion component to it that ACDC lacks. ACDC I would say are classic rock, hard rock but not Glam Rock. Unless the school boy outfit does it.I actually had to look that up myself and sure enough Guns n Roses and AC/DC are in Glam band category. Perhaps definition of a Glam band goes beyond than just the makeup shit.
From wikipedia
AC/DC are an Australian rock band, formed in 1973 by brothers Malcolm and Angus Young.[1] A hard rock/blues rock band,[2] they have also been considered a heavy metal band,[3][4][5][6] although they have always dubbed their music simply "rock and roll".[7]
Similarly GnR is not Glam they were considered opposite of it in many ways...... they have very little in common with Poison, Cinderella and that ilk.