Which one did you get?
Yes they are both in store in all colours. I got the smart case in black and very pleased with it. Fits very well and feels great.
Does it make it feel a lot heavier?
It does make it feel a bit heavier yes but still noticeably lighter than my iPad 3.
Bought both the brown leather Smart Cover and the black leather Smart Cover. Haven't opened the black yet but the brown looks very nice on my white iPad Air. And matches the two Apple cases I have for my white iPhone.
There are no leather smart covers for the Air. I take it you mean the cases. The smart covers are only available in polyurethane.