Leveling the cab

[72Mountaineer]

Are the rear cab mounts supposed to be flexible? I'm in the process of mocking up stuff, and noticed there are uneven gaps between the running board and the bottom of the cab at the rear mounts. Do you just get the sides even and tighten up the bolts where the bushings are? The assembly manual gives a dimension of 3/4" between the frame and cab floor, mine will be closer to 1"plus in order keep the gap between the cab and running board close from front to back. By the way, its a '53 3100.