Isn't the whole book of Job about Job's salvation? About whether Job's soul would belong to Satan, or God?
The question of how one was saved in the Old Testament comes into play. For my part I would say it was the same in the Old Testament as it is in the New Testament. We all have to put on God's righteousness. We have to be clothed in God's righteousness. After Job repented he lived another full life without comment, other than his daughters where the most beautiful in the land.