If I knew I was being pulled over, I would try to refrain from any odd or potentially suspicious (i.e furtive) moves, like digging around, or reaching into pockets.
I happen to keep my wallet out of my pocket, and in the cupholder or cubby on the dash.
When pulled over, I turn off the ignition and turn on the interior lights (especially at night - full visibility for the PO). Hands remain on the steering wheel.
When I was recently pulled over (once for a burnt out headlight, another for a burnt out tail light. Dang cheap Walmart replacement lamps), things were courteous, professional, and ended with a verbal suggestion, no ticket.
In one instance, the PO asked for my DL, so I handed him my DL and CC permit, and timidly informed him I was carrying. (I admit my voice was shaky - first time ever pulled over while carrying). He said "I appreciate you telling me." Then noted "You seem nervous" - I replied simply "yeah - never been pulled over while carrying before." The PO seemed to relax a bit, and said, don't worry just keep your hands away from the firearm, and I'll be right back while I run some things." A few minutes later, he came back to say "everything checks out OK. We really appreciate you telling us when you carry. Just go get that light fixed and have a good night." And that was that.
In the second instance, the PO asked for my DL and also asked if there's anything he should know about in the vehicle (I appreciated the humor, when he added "guns, bombs, nuclear weapons..."). I said yessir, and present my DL and CC permit, and informed him that I'm carrying. He asked where, and just said to keep my hands on the steering wheel or wherever, just stay away from your firearm. Again, just a verbal admonition to get the lamp fixed (which I did that evening).
Of course, I might fit a profile that also helps (clean cut but frazzled dad, in a minivan or suv, drowning in kids toys....). In the MN case I hesitate to speculate, but the driver may have fit a different "profile" (understatement here), but the PO gave poor instructions, and it ended up in a highly questionable shoot (another understatement).
Why wait for the PO to get to your window? If I know I'm being pulled over, I grab my wallet from my rear pocket before he's even out off the car. I keep my insurance and registration in my visor that has a fancy little sleeve to hold it, so there's ZERO reason to open my glove box.
As I said before, there's no reason to mention my firearm during a traffic stop, since the gun isn't driving or involved in the possible driving infraction.
However, if they ask, I'll let them know. Otherwise, it's an unnecessary topic to bring up.