The cut of the frock is different (most noticeably at the bottom front where, as Svenn says, the skirts are rounded rather than straight) and there are pockets with some fancy lace and buttons (or false pockets that are just flaps, not sure which) below the level of the belt. The cuffs are radically different, too. None of this would be too difficult to convert though, I don't think.
The Osprey British Forces in Zululand 1879 has a nice colour plate with an officer, a sergeant, a piper (whose uniform appears to be dark blue) and a private. Would be very useful if you do decide to convert.