Does Peter teach that Christ is the head of the church in Acts?
No. In the Acts record, Peter never teaches that Christ is the head of the called-out assembly, nor that believers are part of His body. That truth is absent from his preaching. The headship of Christ over the church is taught in Paul's writings.
Les teaches that in the Acts record, Peter never makes mention that Christ is the head of the called-out assembly, nor that believers are part of Him. He points out that while the same Greek word Ecclesia is used, Paul's writings introduce a new connotation: the church which is His body, whose head is in heaven and whose members are the body. Les stresses that it is just as important to see what Scripture does not say as what it does say, because many have assumed things are in Scripture when they are not. So Peter's preaching in Acts lacks this headship truth.