Yup, the 57 is a worm and sector, the 58 is reciporcating ball. It is a bolt in but be advised the horn wire for the 57 runs down through the shaft and comes out the end of the box. The 58 horn wire comes out with the turn wires inside the car.
As a side note, boxes thrue 64 bolt in along with the pitman arm. 57 - 60 have the one piece steering shaft, 61 - 64 use a rag joint.