A tour pro's clubface may be open or closed relative to his feet alignment depending on which way he wants to work the ball, but you can bet it is nowhere near 5 to 10 degrees off of the target. That would make him have to compensate by 5 to 10 degrees to get back to square to the target.
Virtually no PGA Tour player has the clubface "square to the target" at impact. Almost none. They're all aimed left or right of the target at impact to account for the fact that the ball will curve.