Sort of. Was open carrying in a mall in Washington State. I did not stop to read the two page black with white print notice of Code of Conduct (or something like that). I instead just looked for the typical no weapons signs and didn't see any.
Two city PD officers (not mall cops, real cops) stopped me and told me the policy was no firearms. I mentioned I didn't see it posted. They said it was in the Code of Conduct. They also said, just cover it up (did not even ask if I had a CPL!) and everything is fine, so that's what I did. (I do have a CPL, by the way).
But if the sign specifically says no CONCEALED weapons, that's what it must mean the owner's desires are, so one would assume a non-concealed weapon would be allowed by the owner.