Welcome to OCDO! (open carry dot org).
I'm glad your police encounter was relatively uneventful.
I have a few questions that will help me understand the legality of the police actions.
1. Police came onto your private property while you were mowing your grass?
2. The police detained you, meaning seized you temporarily? Or, were you totally free to ignore them and keep on mowing?
3. Demanded your firearm permit? Or, you volunteered it?
4. You complied with everything demanded and/or requested without politely, verbally withholding your consent while complying?
5. And, answered at least one police question without invoking your 5th Amendment right to silence and 6th Amendment right to counsel?
You consider the police were nice about the call? You see, I disagree that the police were nice about the call. I think you were misled by politeness on the part of the police. See the posts that follow.