Peter,
'32-'34 drums are the same while those for '35 are unique to that model year. Where the "Rocky Mountain" tag comes from, I guess, is that all of the '32-'34 front drums and some '35 drums are partially open in their construction leading some to conclude that they are vented. However, when the wheels are installed those openings in the drums are completely covered up by the wheel hubs thereby negating any 'venting'. In other words, "Rocky Mountain" is a misnomer carried over from Model T days when used to describe those drums.