Today, the vehicles have flimsy jacks, independent suspensions, and uni-body construction - very few strong points under the body.
Out trucks have strong frames and full-width front and rear axles.
Since bottle jacks were the "standard" (optional, usually) GM implement for our trucks, my guess is that you put it under the frame, under or near the front or rear axles, and jack it up (to remove a wheel).
Later vehicles (cars) used bumper jacks to lift them to change a tire.
