Agree about standard procedure and wish there was one ...
Been stopped twice since last summer and I did the same thing in both cases ...
An Arkansas trooper stopped my wife and I on a vacation trip to Branson, MO in a rented car ... kept my hands on the wheel, when he got to the window, I told him I had a Texas CHL and was armed ... he asked for my license and CHL and asked me where the gun was .. told him it was in a holster in the door pocket, he told me to leave it there and to exit the car ... then things got a little weird, at least from my point of view ... he asked if he could pat me down; I said sure, advising him there was a pocket knife clipped to my pants pocket ... then he sat me down in the cruiser, told me he'd pulled me over for allowing my right front wheel to cross the curbside white line (on an interstate) ... then he proceeded to talk to me about guns, asked what I was carrying and whether it would make a good backup ... let me go with a warning ...
The second time was in my little dinky town in TX, pulled over by a constable for not having a front plate on the car ... same routine, never asked to see the gun, gave me a fix-it, which I did the next day ...
In both cases, I kept my hands in sight and did not start reaching for my wallet until he had asked for my papers and could see what I was doing ... both were educational and sort of entertaining since I didn't get ticketed in either case ... my advice is don't fumble around for your papers until the officer asks for them and can watch you doing it, and tell him or her when they get to the window that you are legally armed if you are ... I understand the law may not require notification; I just do automatically as a courtesy .. LEOs have a tough enough job dealing with people on the wrong side of the law; anything you can do to ease their minds when they approach your vehicle is a plus in my mind ...