The up and down keys are half-height without a spacer between them. Together they take up the same space as one letter key. That's the way it has been on Macbooks for a while.
The change on that keyboard is that the left and right keys are now full height; they used to be half-height with a half-space above.
The change on that keyboard is that the left and right keys are now full height; they used to be half-height with a half-space above.