Hardened Oil Pump Identification

Man. That's a tough call. If I had to guess, I'd say it's not a roll pin. I think 1/4" would be way too big for that shaft anyway. I think a hole that big would weaken it to the point the roll pin didn't matter. I'm unsure it's something to worry about. Have any of yall ever seen a pressed on gear spin on the shaft? I have not.
The old one shows no sign of a pin and it had been spun up pretty good a time or two on the HV pump. Its not a roll pin for sure.