The only NO CDW restriction sign I have seen is in the Lady Lake Post Office.
This site may answer many questions. The trend for the last 30 years has been toward less restriction on carrying weapons. If you surf this site that will be explained in a year by year graphic. It explains the permitting requirements state by state. Personally, I have two state CDW permits and a third that is nationwide.
http://en.wikipedia.org/wiki/Conceal...tates#No-Issue
State by state reciprocity maps...very informative.
http://www.handgunlaw.us/