only les paul juniors and specials have no maple top, and the sporatic custom. 99.9% have a maple top. the difference between a junior and a mahogany/maple body? a lot. the first has more bite, more crunch, the latter has more bottom end, more growl, more 'more'. a mahogany back + mahogany top gives a warm, smooth sound with a lot of 'sponge', very open.