Some states do recognize out-of-state civilian CCW permits. Some do not. I know the State of Florida is one, in particular, that will issue you a CCW as a non-resident of that state. I believe, last I heard, there are 28 states that will honor that permit. CA is not one of them. I believe there are just a few states that allow any non-felon to carry concealed; Florida, Vermont and Texas, come to mind.
LEOs had to fight many years to get a blanket nation-wide CCW for LEOs. Many feel this was the first step toward a nation-wide CCW for civilians. Some civilians were against it, feeling it should have been made for all CCW's and not just LEOs. Whatever the case, police unions and LEO orgs. spent millions getting this federal law passed (HR 218) and even though the final version was cut up like swiss cheese, it passed and we have nation-wide concealed carry for cops.
Essentially, if you have a current LEO CCW-endorsed ID and a current (within 1 year) firearms qualification with an LE agency, a qualified LEO has the same rights to carry concealed in all 50 states, as if they were doing so in their local jurisdiction. No sooner than that law passed, NYC and D.C. attempted to get injunctions to prevent the application of that particular law in their jurisdictions and prevent LEOs from carrying concealed when visiting there.
Keep in mind, Police Chiefs and Police Commissioners serve at the pleasure of their Mayors (or elected City Managers) or city-councils... that makes them slaves to politicians. Rank and file LEOs usually see things differently than Chiefs of Police. So, when you see something is supported by associations of police or fire chiefs, that does not mean (in the slightest) that is is supported by Law Enforcement Officers or Fire Fighters. This is a distinction that is all too frequently lost among the public. The Organization of Police Chiefs came out AGAINST HR 218, while every true LEO organization was in favor of it. That is just one example among many.