Jon,
Once the cushions are out there should be 4-bolts holding the frame to the sliders (2-each side). Once they are out you undo the cable from the slider 2-bolts (one each side). That is all that holds the frame in on the 47-50 trucks. You may want to soak them in PB blaster for a day before you try and undo them as the back two collect crud and rust and often break.
