If you need regulators, I have a one of each. If it is the sliders, you can get rollers to replace them at any parts store.
What year, and model is the car. The 94-96 RMW is different from all other panels. The 91-93 door panels are different from the 94-96 Caprice panels as well. Rear 91-96 Caprice, and 91-93 RMW, and OCC panels are the same design, but the colors change for some years.
The early year front panels can be modified to fit the 94-96 Caprice with the swap of the front corner panel.
If the lower panels are not extensively damaged, they may be able to be repaired. They may not look new, but they can be made serviceable, and if painted with SEM, the repair may be virtually invisible.