Been the way for a while now. Even the 1 series I had was a 116d but I believe the 116, 118 and 120 were the same engine just tuned differently.
I've just got a GLC 220d but the 220d and the 250d share the same engine.
The real cheat is when you look at the C63 AMG and it's far from a 6.3 litre engine inside!