if the po did the head gasket with the intention of selling the truck quality may not have been a top priority and steps where likely overlooked. you cant put a gasket between a warped head/block and expect it to last. machine work is often needed. changing a head gasket is not exactly fun so if you do it do it right. factory gasket is the ONLY way to go. id suggest replacing the timing chain aswell as the guides/tentioner and the oil pump check its condition or get a new one.
