340 CRANK?

On my other 2 stock 340 forged cranks - 1 has the notch in the flywheel flange, like the above picture shows, and the other one has no notch. Any ideas on why the difference?

AJ/FormS- Do any of your forged cranks not have a notch?

D.Dog- I bought this mostly complete 340 from a guy in Monroe, Michigan. He didn't know what 69 it was out of (Dart or Barracuda). The block is dated 12/9/68. Sorry I don't know more history on this engine.