At about 05:55 in Scott Manley's new video NASA Might Be Giving Away A Saturn I Rocket - Here's Why I Love This Vintage Booster he says:

So the Saturn; the first four blockone Saturns, they didn’t have the fins. The block two, they got the fins, because of course this is a rocket by Von Braun.

Why did the block two Saturn I rockets get fins "because of course this is a rocket by Von Braun"?