http://stackoverflow.com/questions/14233336/software-buttons-height
My assumption is right.
to generalize question and prove it, here manual measurement what I have done on telephone and tablet from screenshots :
SOFTWARE BUTTONS HEIGHT
portrait: 48 dp
1280 - 1184 == 96 px == 48dp xhdpi
landscape: 42 dp
1280 - 1196 == 84 px == 42dp xhdpi
( attention!: in landscape, this is not height but width of software button placed on right side of screen)
portrait: 56dp
...
landscape: 48dp
...
