No. All current models are (although the Freelander system is fundamentally different to the others). Series Land Rovers (pre 1983 ish) are part-time 4WD, except Stage 1 V8.
Transfer box takes input from the main gearbox and transfers it to the front and rear axle, or to the rear axle only in 2WD mode. They also have two different gear ratios - high and low.
Tim Hobbs
'58 Series 2 '77 101FC Ambulance '95 Discovery V8i