If solenoids are replaced the injectors should be recalibrated which is a good bit of labor on top of the cost for new solenoids.
Not that they won't work with just swapping solenoids. It can and has been done with varying degrees of success. That said, fuel deliveries will be all over the board and it won't be right. Also depending on the amount of heat that went into them, the high pressure seals in the bodies are likely toast.
