The 707 features a system like the 727 where both things (FD and AP) are separately driven.
So the FD can show you one thing while the AP follows another. The modern planes usually link those two systems, so their FD will show you where their AP will point to (when activated).

So if you want to have both on the 707, a FD showing and an AP driving you in the same direction, make sure to both operate them in the same modes. E. g. "Nav" on both would fit here.