.020 under on the rod journals should be no problem...All the strength in that journal is in the pressure rolled fillets in the corners...The .020 smaller diameter is not going to weaken the journal any...If the crank is going to break, it will break in the corner, where the pressure rolled fillet is, not in the middle of the journal...Since the diameter of the rolled fillet doesn't change, the strength of the crank shouldn't be affected...
Just have the crank crack checked...You will be okay...