Doesn't matter. I could have created it with dice-rolls in my bathroom. As soon as you have a public key, you can add it to your kind 3. You might need to use a tool like NAK or Nostrudel's note publisher to manually edit your kind 1 if searching for the npub in a client doesn't let you follow it.

What are you specifically testing for, though? Kind 0 profiles shouldn't just exist on a WoT relay. Those are meant to be spread far and wide, so you can always just create a profile for the new user that is saved to a few public relays before following the user to add them to the web-of-trust.