https://www.gm.com/content/dam/comp...hevrolet-trucks/1980-Chevrolet-Truck.pdfThat document shows the Chevy had leafs. They don't have GMC in the Heritage Center Archives, and I don't know how many (if any) mechanical things were different between Chevrolet and GMC in 1980.
RockAuto only shows coil spring parts available for the front, and only shows leaf spring parts available for the rear for a 1980 1500 with a 250 six and a 454, so I'd assume the engine filters in between those sizes would have the same suspension parts listed. Take that at whatever value you place on the accuracy of RockAuto's parts listings... I just checked there because I knew it would be fast to drill down to those items.
