a hand brake was not "optional", there were 2 different setups - if it's a light truck with a 3 speed it had a lever under the left side of the dash for cable operation of the rear brakes - med & heavy trucks with the 4 speed had a driveshaft brake with a lever next to the shifter thru the floor
either e-brake arrangement isn't simple, there are a range of pieces, and if you don't have any of either version your best bet is to get the 55-59 assembly manual so you know what you're looking for, or find a nearby truck of the same model [55-59, 1/2, 3/4, 1T] to borrow parts from .... there's also some helpful pics in the shop manual, which can be
found hereBill