In 1995 there were 2 optional ABS systems installed on E350's.
1st and most common is the Kelsey-Hayes RABS II, which is a rear ABS only system.
2nd but not uncommon on 1 ton's is the Ford ABS-4WAL, which is a 4-wheel ABS system which has 2 more sensors on each of the front wheels in addition to the rear diff mounted sensor.
This system was not available on Pick-ups until after '97.
If you look at the front wheel area...next to and/or attached the soft brake hose will be an additional tube that houses the wires going to the front wheel speed sensors. There will also be exiter rings on the inside of the rotor hub to trip these speed sensors.