I had a momentary panic after posting - I don't have the current
GK codex, but I do have the previous version, which has the three
LR variants in it (Phobos, Crusader, Redeemer). So perhaps I shouldn't have said "definitely", but I
strongly doubt
GW would have removed them (and I'm sure someone would have corrected me otherwise).
So as long as what you wanted was a
GK land raider, you're fine. A standard
DA LR would only be slightly different (no Aegis, etc.), but if you were wanting a Deathwing
LR, then you will need the
DA codex, as it has additional rules.