Are believers in faraway places like Bolivia part of the same body of Christ as believers in America?
Yes. Believers in faraway places such as Bolivia are in the same body as believers in America. The context states they are in the same body, all members of the same organism, that spiritual makeup of believers from wherever they are and whatever station in life.
Les uses the example of missionaries who had believers down in the jungles of Bolivia, and he says those believers are in the same body as believers up in Oklahoma and the rest of America. He explains that all believers are members of that same organism, that spiritual makeup of the believers from wherever they are, from whatever station in life. He calls this crucial to understand. This fits the broader context that Paul speaks of the Body of Christ, the Gospel of Grace, and believers of the Gospel of Grace being many yet one body in Christ, members one of another.