Crank journal wear can be felt with the finger nail as, the shape of the shell. The centre part of the journal never touches the shell so, the worn part is always the two sides of the journal. The only time the centre part has any wear is, if the oil has contaminates in it.
Just think of a crank rotating at 5,000 rpm for 40,000 miles, you will find some sort of wear to the running part of the journal and shell.