I don't know much about this subject when it comes to SKS barrels. However, AK barrels are stamped with a series of numbers to indicate the relative size of the journals. "1" is for undersized, "2" for nominal, "3" for oversized, etc. This indicates to me that Com Block manufacturing is not quite as precise as we might hope -- I imagine that you will need to do some research before assuming you can swap components from one barrel to another.
Larry