TSMB, I remember adding a set of Addco anti-sway bars to my '72 Duster in '75 or so. But I don’t know when Ford might have started with them.
Most cars with independent front suspension had at least a front sway bar even in the early '60’s… Performance models had them front and rear. Back then, the big limitation on road-handling and traction were the unbelievably poor bias-ply tires…
This car would have come with wide oval bias belted tires. Not as good as radials but a lot better than bias ply alone.
I can’t remember if my Montego had leaf springs or coil springs in the rear. The cars of this era that had coil springs did not need a rear anti-sway bar. The trailing arms and the axle housing served the same function. In fact they worked a little too good which may be why a lot of them tended to oversteer.