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Actually, according to Richard Ogorkiewicz in Jane's Technology of Tanks (1991), interlocking armour was used in later tanks and light-armoured-vehicles.
In the chapter on Armour protection he notes that stepped joints were used in the American M-551 Sheridan light tank (entered service in 1969), the British Scorpion light tank (entered service in 1973), and the French AMX-10 tracked armoured-infantry-vehicle (also entered service in 1973). [p368]
It's perhaps worth noting that the references to stepped armour here are in the context of aluminium armour. Ogorkiewicz states that:
... aluminium armour is easier to machine and the greater thickness of its plates makes it possible to use stepped joints, which provide a partial interlock between plates and require therefore less welding.
I'll see if I can a copy of the reference online.
EDIT: The reference is available on Internet Archive. I've added the link above.