Half-soles = solid stacked leather heels... eg, on Vibram composite half-soles
Full sole unit = "alternating black/natural" heels [natural trim option]... eg, Vibram 100, 700, 430, etc.
as for the Classic 2012, it just came out around the 2nd quarter of this year, so i don't think you'd find much here nor the in the other forums just yet.
i am planning to get a pair built [in black leather combo], but still trying to dial in on sizing for the classic 461 last.
... any1 got info on sizing?!
Natural is standard? Or the stained/darker sole?