About a year ago, our local post office had their no guns sticker on the front door. Last I was there, the sticker is gone, do not know where it went, but no longer on the front door.
Anyways, as my wife says, no one will ever know. So I usually go in there with my CCW on me, concealed. Imagine that. Never had a problem, even with the huge clip of a Lone Wolf Harsey Tactical hanging off of my right pocket.