The engine mounts basically do the same thing structurally but above the engine intakes are small inlets for cabin pressurisation and other air-driven supplementary systems. On some aircraft these are only fitted on engines 2, 3 and 4 (or engines 2 and 3 only on some 720Bs).
I'm sure there are tonnes of photos in the database that will support and / or undermine my point. Hope it helps.
fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz