The inner bogies are certainly well back of the outer bogies but I haven't been able to find a scale drawing of the undercarriage of a B-747 Classic.
Plate 11 in D P Davies's "Handling the Big Jets" (3rd ed) is very instructive. It shows a 747 Classic undergoing high-AOA takeoff tests with a deliberate tailscrape. The hindmost four wheels of the inner (centre) bogies are the only wheels in contact with the runway as the extreme tail scrapes the ground.
Rockhound