Does every believer have something God-given that can produce rewards?
Yes. Every believer possesses at least one God-given gift or ability, though believers do not all have the same gift or serve in the same area. That gift can be used in service, and when exercised it can precipitate or produce rewards from the things done in the body.
Les explains that salvation is a gift of God, but once a person becomes a recipient of that gift, God logically expects that believer to go to work and work for reward. He stresses that believers are not saved to sit but saved to serve, and this is going to be brought about at that seat of Christ. Les also distinguishes rewards from crowns: crowns such as righteousness and life are listed, but they should not be confused with rewards. Rewards are what believers receive as a result of what they have done in the body during this earthly sojourn. In Romans, Paul listed gifted men given to the church, showing that not everybody has the same gift or works in the same area for reward. Yet every believer has something God has given that can be used as a gift, and that gift in turn can precipitate their rewards. Paul alludes to this in 1 Corinthians chapter 9 by inspiration of the Holy Spirit.