Yes, I had to double take as well. Thinking back to Highbury pre-Taylor Report, I am still struggling to envisage that big a stadium in the confines of the community in which it stood. There would have had to have been three-tiered stands with double decker terracing / seating at either end. Even then it would have been a push.
Never let it be said that the board of the time were not ambitious. You wonder what the ground would have looked like following the requirement for all-seater and later modernisations. A monumental undertaking and most likely, financial suicide with the onset of the Second World War at the end of the decade. Certainly a big target for the bombers during The Blitz.