Yes, trucks this small can have hydraulic system power brakes.
It is not a brake booster either.
With Toyota hydraulic system power brakes, you have a brake valve mounted on the front bulkhead that is fed hydraulic oil from the hydraulic pump. The entire brake system piping is filled with hydraulic oil all the way to the wheel cylinders.
Foot pedal linkage operates the brake valve to allow oil pressure to operate the wheel cylinders when service brakes are applied.
With these systems of old, a hydraulic pressure accumulator was included in the scheme to provide a back up brake pressure source if the engine dies or the hydraulic pump quits.
I don't know about the 2F and 4 F, models but I know for a fact that 3F models had this system and later 5F models have it too.
To my knowledge, beginning with the 6F models, hydraulic system power brakes are no longer available from Toyota on the 25 rated of trucks.