Is 1. d4 Nf6 2. Nf3 e6 3. c4 d5 called Queen's Gambit Declined when there is no gambit offered, let alone declined? I understand that the opening 1. d4 d5 2. c4 e6 3. Nf3 Nf6  is called Queen's Gambit Declined. But how about 1. d4 Nf6 2. Nf3 e6 3. c4 d5? There is no gambit offered, let alone declined. Is it still called Queen's gambit declined?
Yes, it is still called the Queen's Gambit Declined. That's just the name of the system, regardless of the move order used to reach it. However, it is not the QGD before Black chooses to push 3...d5.